I came across a post from a kid, it was this one: How to calculate the opposite of a number? Some members find this types of question to easy, lets call it "trivial", so they rated this question -1. The question was correctly tag, pre-algebra. To rate a question from kids negative, is not a good process, "in my opinion" at least. It stops them from asking more. From my point of view mathstack is the best way right now on internet on asking a mathematical question, since the quality of answers is great.
Maybe preventing the questions in certain tag to go negative? Are you working on a solution to this problem? I did not see any hints in the FAQ addressing this Problem.