The older I get, the more I think that helping your kids avoid interactions with others who aren't with the program is for the best. Ideally your children's friends should be people that you think are good kids, kids that you would go to bat for. Then when you are teaching your kids to compromise and play nice and forgive, you can legitimately feel good about it. I think my default assumption about a negative interaction with a public school random would be that they are basically a wild animal to be avoided.