We have no dangerous kids,but we did get a securiity system for our new house and we put motion sensor lights all over the house too. Anyone who would walk by would light up our house, yard, everything. We are in a rather dark cul de sac so we took this extra precaution. Our area has almost no murders but lots of druggies who often break into houses to steal so we did extra protection. Asking cops we know, we were told how to deter these drug users. Along with our six foot fence in back, we feel safe. We have a system where you need a password to get in or the police are instantly notified. We dont have to call. They will be notified by those from our security systems call center....I think thats how it works. If your son is a danger to you, I agree it is better to be safe and not let him in or give him the opportunity to break in and steal or confront you. You both dont need that, him either. In a confrontational relationship, distance is your friend. Your home is your sanctuary.