A lot of those false positives are going to be things that look very much like a true positive to an underpaid, overworked moderator. I don't think 15 minutes w

A lot of those false positives are going to be things that look very much like a true positive to an underpaid, overworked moderator. I don't think 15 minutes would cut it. Actually, I'm not convinced that any amount of time would, because there are too many occasions when the distinction between hate speech that must be banned and social justice speech that only a bigot would ban rests entirely on the social standing of the person making it within the appropriate circles. Also, I strongly suspect that Google, Facebook, etc are already applying this kind of manual scrutiny to potential false positives behind the scenes - as you say, it's relatively cheap - and this explains a lot of the problems people have been having with their moderation decisions and why appealing decisions so rarely works out.