Administrator can check their IP and compare it with mine, I bet I'm the only one who have bitcointalk.org account in my country.
I could deny that those accounts are mine, because he have no proof I'm their owner, but I didn't because the admin can easily check from which IP their created
with. I'm challenging him to give me any proof that I control those accounts.
Ips can be spoofed and you know that. It's very easy to create an account on your original IP and then start using Tor or a VPN later down the line. Your right you probably don't own a lot of them anymore because you've sold them.
If they were hacked and you were obviously making money on them why wouldn't you try and recover them?