The problem with that is, because i know first hand, one can merely throw in another network card which will give them a new MAC address but you wouldn't even need to do that because there is software out there that allows you to change the MAC address of any network card. I can only sympathize with how pissed off you must be, people like this thrive on the fact that they're "unstoppable" and the more you try to stop them the more it fuels their stupid belief and excitement. I've had my MAC address banned before but, as i said, it's easy to get around so it's pointless to ban that.