Your question about social development is a good one. When my children were young, I was concerned about this myself. Children are open and easily drawn in by those who don't always have kids' best interests at heart.
This is why I have raised my kids to recognize those who bring out the best in them versus those who manipulate or intend them harm. In my parenting book, one of the novel techniques I teach is how to use the natural world to teach your child about human psychology, so they can begin to recognize those (whether other children or adults) who want to use them for personal gain.
Using these techniques, my children (who are now 12 and 15) have grown up to be quite psychologically savvy. This gives me great comfort as a mother because I know my children will not be tricked by the sociopaths among us and that they see through the polished exterior of those whose niceness is only a ploy for manipulation.
Of course, it is my children's job just to notice those who actions don't match their words and inform me about it, particularly if we're talking about authority figures here. As a parent, it is my job to do something about it.
