They Joined Same Bounty , They Transferred Their Token In the same address,
So? Can you prove that the address they sent to is owned by someone that controls all those bitcointalk accounts?
Do you even know who the owner of that address is? The answer is no.
You have no real proof that ties half of those accounts together. Don't get me wrong, I'm not trying to defend cheats... and I commend you for trying to catch them... but you can't just point to two accounts, say "they transferred tokens to same address... they're alts... ban them"... that isn't how it works.
Two addresses that transfer tokens to the same address are not necessarily alt accounts. You need more proof... like:
Name: Account1
ETH addr: 0x123456
Name: Account2
ETH addr: 0x123456
In this instance, Account1 and Account2 both "own" ETH addr: 0x123456... given that only 1 person should be in control... it is a fair assumption that Account1 and Account2 are the same person.
What you have is:
Name: Account1
ETH Addr: 0x123456
Name: Account2
ETH Addr: 0x987654
See how there is no link there? It's just two accounts, with two different addresses...
Are they likely to be alts? most probably... but you still have no actual proof.