If 3+ is central to the story, then please advertise it!
We're kinda using tags to serve two roles, one to warn about objectional content, and the second is to advertise. I’ve been keeping mine to the first purpose, because that makes it easier to apply them where needed. But, if people are treating them as advertisement, that’s where it gets tougher. That’s because using abortion] for mentioning that “Ms Charming” had an abortion, is different than [abortion] for describing the fine details of the procedure, a distinction crucial to somebody looking for a fic centered around an abortion.
I’ve given this some thought. We could, for instance, tag each chapter with a severity rating, *but* such a system would be very prone to leaking spoilers if you know that chapter 7 has [abortion++], chapter 10 has [MCD], with [nec] in chapter 11; plus the time to code it up, get people adjusted, etc.
In the end, the simplest solution is to keep doing what we’ve been doing, tag as a warning to objectional content, and advertise via category/summary.
That’s my $0.02 worth on this.