Or let them keep playing but instead of resetting people back to prestige 0 level 0 let them derank themselves by everything they do in the game removes 1 from there stats and challenges,so if they get a kill it removes a kill from their stats if they get a 10 killstreak it removes 10kills from their stats and takes the title for 10 killstreak off them,every level they should rank up takes 1 away and when they have deranked everything off themselves then they can start to rank up again.
So everything they do is in reverse till they have no titles no stats no rank,then they are allowed to rank up again.
That actually sounds like a fun challenge. Personally I like the idea of perma blackbird for 2 weeks and a notch on their emblem that identifies them as having cheated. These people like to seem cool and brag about how much better than everyone else they are, so take that ability away from them so everyone can see they cheated at a glance. Oh and make it specific to the console and not the player account so they can't just make a new one.
id like to think they would be able to change the glitchers "prestige masters" into "he hacked prestige master - aim for this guy!"