I have learned to quickly sort people out by telling them about whatever is the most improbable project I'm fiddling with at the moment. The project is unimportant; what is telling is their response. I get one of three responses, no interest, that's cool, or you're an idiot. Quickly tells me whether they're worth further time or not.

Yes, but in such a system, one would also probably lose a dollar every time they said that mistakenly.

In a way, we are in such a system. This is what makes startups so dandy!