I also, personally, don't need warnings. For anything. If I encounter something that truly squicks me -- and, yes, I have squicks, mostly bodily functions squicks -- then I either choose to continue reading or I choose not to. It's really that simple. And you know? I have triggery things as part of my life experiences, but I don't feel the need to be warned for them.

Of course just because I don't need warnings doesn't mean someone else won't. It's okay to need warnings, but I think if you're so sensitive that you need a ridiculous level of warnings, then you ought to bear that responsibility yourself (again, see warning for bees or the word rape)

I hadn't thought of the whiteout technique, but it makes a ton of sense. Of course it only works with people who have white as their reading background; I myself happen to have black.