Spent some time in Brooklyn last year and saw these everywhere. I concluded that the hats were for converting them to dreidels when you bumped them with your vehicle, they would spin better.

Joking obviously, but one thing I found was that they would look right through you and not acknowledge your presence as if you didn't deserve the time of day. This was universal among them - as if their own people were the only ones worthy of interaction. Polite "hello" nods were coldly ignored.