Have you guys informed the same to their campaign manager? Also, correct me if I'm wrong but don't you have to be a Junior member and above to join a bounty campaign? Any campaign that allows newbies to join the campaign will have flooding of alt-account and cheating. You are doing a good job busting them but if you look at the bigger picture, these accounts have not much to lose, just takes them seconds to create a new one and join the campaigns again.