Interesting topic. Good thread. I have been here only a month, and so far I find these forums to be a terrific resource.
I'm not seeing how a forum such as MO (or to a lesser extent MSE) even could be able to stay the way it is without some harsh screening.
THAT SAID, no one can know everything about math, although sometimes we all feel that we need to. This is what I mean: I am a research mathematician who has used this site to ask math questions that happened to come up in my own research, and that happen to be outside my area of expertise. So chances are the questions are fairly basic to an "insider". For example, I am in graph theory who has needed to be able to "get" a theoretical construction that uses a lot of high-powered number theory so I've asked questions about number theory that probably aren't near research-level to the insider. Maybe several others on here have done likewise. Anyway, I have gotten good answers, BUT (a) I do my best to explain my predicament, and (b) I make a point about being as clear and specific with the question as possible.