BDSM and rape
Never understood "trigger warnings". Talking about rape, discussing rape, looking at it from rational and removed points of view is actually good for most victims. It helps them contextualize it and deal with it. Though admitedly listing to idiots justify it is maddening.
Most vitims (of anything) have triggers like a particular smell, a sense of isolation, a touch on the wrong part of the body when their minds is wandering, etc.
(sorry, just sorta bugs me all the "trigger warnings". I mean, for god sakes, the article says "RAPE" right in the title. If you can't figure out we are going to talk about rape....)

I think we discussed this before. The overwhelming hurdles a woman (or man) faces when the whole point of the sexual relationship is to push "vanilla sex" standards, to "abuse" (by the outside world's eyes), or even in some cases to "be raped" sorta. or enact that, anyhow. Saying "my boyfriend raped me" is hard enough to get anyone to care. Saying "I had had sex with three men that night, but said my safe word for the 4th who I didn't trust" is going to get zilch attention outside the community.
But as this is the second report you are showing me, sounds like within the community there are voices being raised. Though the responses are very blame the victim-ish. "know your partner well", "ask around". If people close ranks, neither of those will be very effective.
And I hadn't even onsidered the "unintentional rape" that goes along with her point on "miscommunication". That you *think* your bottom is enjoying something, and you want to give them a good time and push the limits, only to find out you read teh whole scene wrong.

I read a blog post entitled "Trigger Warning: Cathy Brennan". Then I understood. I suggest the concept gets appropriated for extreme idiocy so we can at least strap pillows to our desks in advance!
But I understand your frustration with the warnings. Whenever I read "trigger warning", the article invariable doesn't seem to go into that much detail. When I read "trigger warning: in depth and frank discussion of rape and abuse" I expect it to deliver on that promise (dear Loaaard that makes me sound like a terrible person, but you know what I mean) yet invariably it's the equivalent of "I was raped/abused, end of story" with very little supporting detail that wasn't available in the part described by the warning itself! If that sort of thing is enough to trigger you into a flashback or panic attack you probably have far, far bigger problems than can be solved by people sticking the phrase "trigger warning" at the top of their blog post. And then you also hear stories of people having flashbacks and panic attacks after reading something even though they were warned and the article title and abstract was very explicit, but not specifically with the words "trigger warning" - as if the phrase "warning, you may be triggered" doesn't have the exact same semantic meaning. I know we're not supposed to do the "victim blaming" thing but there are limits to how far I'll go to not blame someone for being an idiot.
I guess that's my problem. I do "victim blame" a bit in this context. Not cause i think women and men should "get over it", nor cause i think that they should not read things they want to read, but more because there is this view now, that society should be aware that what they write is or could be "triggers" to someone.
But I'm not kidding when I say most people in group talk about the dumbest things flashing them back. A room with a bed they "remember". A restaurant with asian cooking. Having sex with someone and finding yourself in a position that you've done together 100 times, but this one time makes you say "get off me". The human mind is really unpredictable. By the time you are able to read about and discuss rape, odds are, the word "rape" isn't going to do it.
But I see if you are going to write a really emotional, or first person point of view; if you are writing fiction that goes deep in to description; why it would be worth saying "this is more than your average discussion".

I'm just thinking that (more than?) half the time if the content of an article would trigger someone into a flashback, the warning itself would probably be enough too! Imagine a scenario where someone reads the phrase "trigger warning: abuse etc." and then starts thinking "perhaps I shouldn't read this, then, it'll bring back memories, that's something I don't want to relive oh I remember now... it was... shit..." and full-blown panic attacks just thinking about thinking about it. Yet, without that seed being planted there, perhaps they could have read the full thing without a problem. As you said, it's mostly unpredictable.
Formalising it as "YOU MUST PUT THESE EXACT WORDS AT THE TOP!!!" sort of bigs it up, it adds emphasis, it makes it a far more visceral concept. But a more subdued abstract that explains what you will talk about I think would be more of a reassurance to people. It would completely remove the expectation that reading about this stuff will cause you to have a panic attack - and thus, it enables open discussion that could possibly help people without sticking a big sign on top saying "FEAR IT!!! FEAR IT!!!".
Now I'll really get busted for saying this. but I think "trigger warning' is as much to say "what i'm about to write about is really important, really emotional, and it needs to be highlighted!" the cynic saying "it's just more propaganda".
"Damned rubber neckers, what do you expect to see, a body?"

I could come up with a far more cynical interpretation...
Coming at it from a different perspective, I see it not as a content danger warning but as a general content warning. I write a lot of fanfiction, and there is nothing more irritating than thinking you are going to be getting a nice introspective piece from the summary but it ends up being yaoi-as-written-by-a-tween: male/male sex in the way only a twelve year old could manage to write male/male sex based on highly specific japanese hurt/comfort dom/sub semi-voyeuristic hanky panky graphic novels. Even if you don't have any personal objection to the content within, a huge problem with internet publishing, especially on sites that don't allow sorting by subject, filtering, or many aids to help readers pick and choose the content they get save perhaps a general search or rating/genre filtering (tumblr dashboard, fanfiction.net, fictionpress, livejournal, etc.) so specialized tags, 'trigger warnings,' character lists and notations, pairing notes, or other summary items are popular. It's considered polite to note anything a person might really, really not want to see before they click after the content break and get a face full of stuff they may not have been browsing for.
But other than that, yeah, nothing makes me more weary than watching people try and take the moral high ground by pre-emptively 'protecting' people without a request. It's better, to me, to offend someone once and apologize and fix what's the matter than to assume someone will object to one's content before even a read. It's always better to me to treat people with understanding, politeness, and respect than slapping on a broad label and calling it a day.
If you're writing fiction, i get it totally. though instead of "trigger warning", as if you knew what someone's triggers are, i'd say "graphic descrption of rape", "tepid sex" etc., :-)
someday you'll have to share if you are comfortable.
My writing is bad, so i don't share. :-)

"Warning: Depictions of Tepid Sex" - excuse me a moment while I retire to the back room to PMSL.
I'm 40. been married for 10 years. they say "write what you know". what do you expect????

TRIGGER WARNING: CONTAINS LINK TO TV TROPES,
"He put his thingie into my you-know-what and we did it for the first time."
I think that cropped up recently when talking about 50 Shades of Bollocks, is it the same one that says something like "Harry Potter totally looked like the lead singer of Good Charlotte"?
I dunno if that's a line in it, simply because every single line in the Legendary Badfic My Immortal is so hideously bad I can't even remember specifics. But it does have gems such as,
"WHAT THE HELL ARE YOU DOING YOU MOTHERFUKERS!" It was............ Dumbledore! ,
Snake and Loopin were in da middle of da empty hall, doin it, and Dobby was watching! ,
“You fucking bustard!” yelled Draco at Vampire. “I want to shit next to her!1” ,
and
Voldemort got a dude-ur-so-retarded look on his face. “I hath telekinesis.” he answered cruelly.
Fuck, man, that has to be an intentional parody. There's no other explanation.
"what are you doing you motherfuckers". She can't say pussy or cunt or even "furry gateway to heaven", but does motherfuckers well.

"I'm not related to Gerard Way but I wish I was because he's a major fucking hottie."
A remarkably good troll is the only coherent explanation.
The remarkable thing about My Immortal is that to this day we're not sure if it's a Poe or not. If it is a Poe, they would have to have written a very, very long fanfiction, made up accounts for not only Tara but her friends, and maintained them... as well as maintaining an entire 'offline life' for Tara; within My Immortal, spats with her friends can be seen. For example, she has a falling out with a friend she wrote into the story and graphically killed the girl on-page, only to forget about it a few chapters later when they'd made up. Not only that, but no one ever stepped forward to claim the story, even when it was at the height of its popularity... something that doesn't really fit with a troll looking for attention.
So while it seems incredibly likely to be a Poe, nobody really knows for sure.
But yeah, it's the Worst Possible Thing that fanfic has, containing all sorts of unmarked things nobody ever would want to see, ever. So writing good summaries, tags, pairing notes, and other stuff is very important in the fic community... to avoid running into stuff like this when you don't want it: not so much the quality, but just the... content.
do you have a link to some common tags? yes, i can google, but asking is so much more social!

Common tags? Well, there's not so much a 'list' of standards. They come in a few categories:
Subgenre tags: People will mark a subgenre of some fics, indicating what people can expect from them. For example, a fic that's categorized as a hurt/comfort fic might be sub-genred 'wumph' (more hurt than comfort) or 'fluff' (more fuzzy feelings and comfort than hurt). Romance fics are further categorized this way, as het (heterosexual romance), slash (homosexual romance, but canon gay couples are almost never referred to as 'slash') or any number of things. Fics that are what-ifs, altered setting, or other elseworlds are labeled 'au' for Alternate Universe. Fics that are close to the canon material without romantic pairings outside of what was originally there are often called 'gen' or 'genfic.'
Content warning tags: These help people avoid fics that may have content they don't want to read and are often one-word warnings inserted after the summary text, such as 'rape,' 'torture,' 'depression,' 'suicide,' 'angst,' etc. Sometimes suffixed with fic, such as 'rapefic.' These warnings are also provided for sexual content, such as 'lemon,' (a graphic sex scene within) or 'lime,' (a homosexual graphic sex scene within, less prevalent)... and in fetish circles can be used to identify specific fetishes.
Pairing tags: In fandoms that have more than one possible romantic pairing, people will proclaim which ones are featured in the material so people can find their preferred set. Usually they are either separated by slashes (Link/Zelda) or smushed together to make one term (ZeLink). Pairings are serious business in fandom so not marking them can make people mad.
Other Fic Elements: Some people mark whether their story has original characters (OCs) or not, too... and other details. For example, if writing a fic about the marvel universe, one would need to list what continuum it's set in.
So an example summary that might appear on fanfiction.net might look a bit like:
The Most Rational Fic, by RationalWikian
KnightOfTL;DR and Godot discuss fanfiction warnings. Genfic.
Most of the crap I read on the internet is marked up like M/f, F/m, F/f, MF/ff...
Anyway, new ambition in life: 1) Become famous and popular author. 2) Troll the fuck out of Fanfiction.net with bad fanfiction of my own stuff.
Nah, not ambitious enough. You should become a neuroscientist and try to top Survey Fail.