"I think you seriously underestimate the amount of time it would take to attach such a one-paragraph template / link to every single one of my stories, each chapter, each drabble."
No, no, what I was envisioning was a single warning at the beginning of your Website/profile - exactly what you have now. And if you posted to a community blog or list that required warnings, you could just link back to that warning, like this:
Warnings.
"I read a bunch of arguments, coming from people saying that there were some things generally understood that 'everyone' should warn about, and a lot of very angry, demanding posts from people saying 'you've GOT to do this'."
Demands don't get me upset, because I simply ignore them. But for every loud person saying, "You've GOT to do this," I suspect that there's ninety-nine quiet, polite people thinking, "It would be really nice if you did this." They just don't tend to speak up when the conversations get loud and noisy.
"well, her best tool is her brain, and she should use it."
I'm sorry, but I think this is a bit harsh. There's a middle area between "too traumatized to do normal activities" and "okay with doing all activities."
I don't read erotic het. I just don't. So I like to know when a story is in that category. I'm not filing demands that authors label their stories as erotic het; I'm just saying, very quietly, that if they tucked that information away in some inconspicuous place that wouldn't spoiler most readers, that would be nice.
If the author says, "No, I couldn't do this in any way that wouldn't be a spoiler," that's perfectly fine. It means I won't be reading any of the author's PG het stories, but I understand the author's concern about keeping her stories spoiler-free.
On the other hand, if the author told me, "Your best tool is your brain, and you should use it," I'd be really steamed. Because the fact is that many authors write both erotic het and non-erotic het, and me wanting some authorial help in differentiating between the two isn't me not using my brain. I'm simply noting the fact that "erotic" and "non-erotic" are common categories that many people like to be able to differentiate between. It's not as though I'm asking that stories be labelled as "erotic het featuring D-cup-sized brunettes."
"Trying to enforce a general code of 'Everyone should use warnings' is pointless: some people will not warn."
I tend to think this is a community matter. A community blog maintainer has the right to institute rules. An author posting at their own blog has the right to follow their own conscience. Someone reading a community blog that doesn't require warnings should talk to the community maintainer, not to the authors. And someone who is reading a personal blog should content themselves with making a polite request, IMHO.