Personally I feel it ruins the experience. Granted, if it is a “kid’s” game, I would mark it such. And an “adult’s”, I’d mark it as well. Unless all my games by default are adult. But “adult” does not mean it has sex, just not Barney or My Little Pony.
I may tag it as sci-fi, horror or mystery, as those are wider tags. But as far as announcing other keywords like topics of suicide, sex (not full on), drugs, etc, it kind of takes away from the experience. A player will expect it around every corner till it comes.
Or… I’d mark all my games with trigger warnings, even if they do not have all or any of them. That way no one knows what is actually going to happen and if it does come, the warnings are there. But then quite a few people may over look them, because they do not want to encounter such triggers in a game.
How do you realistically go about it? Put all triggers up and some may get upset the triggers that were posted never happened? Or no warnings and people upset they encountered them? What to do, what to do, what to do…