I see that this thread hasn't gotten any responses, so here's my take. I live in Bedford, although admittedly I haven't been here that long (less than 2years), and my kids are not yet in elementary school. That said, I think there might always be kids who feel the desire to be unkind based on exteriors, if their parents are the same way and haven't taught them properly. But so far I have to say almost all of the families I've met here are very kind, genuine, and wouldn't give a lick what your address is.
I have heard of some "mean girls" behavior in kindergarten, but I believe that kind of thing is starting to pop up all over the country, and can be a function of a particular mix of students in a given time, and not of affluent students being snooty. In this case I think it was something silly like all the girls have short hair cuts, or wear hair ribbons, or some such thing. WhatEVer.