Actually in some countries it’s not, btw just googling Is changing your IP legal, shouldn’t be trusted. And if I did admit to it what are you going to do about it ? XD
Well. Lets just permaban his forum account, lock this topic. CIDR ban him from AoS. Put him on the blacklist permanently. Ban him from the AoS IRC, Blacklist IRC, Pyspades IRC and Aloha IRC. And then be done.