JUDGMENT

I understand that it's just my opinion. But he could join your tournament under a different nickname, changing his IP address (which is possible). And you're already discrediting yourself with your post, claiming that you won't allow cheaters. When this is revealed for the second time, it will be you who looks bad, and it will be because of this statement. But if you had allowed Shadow to participate in another tournament, all his opponents would be wary of him, and under those circumstances, this player would be less likely to cheat again.

I agree.
But will other players want to play with him? Of course, he can change everything, his nickname and IP address... The question is, why?
Does he need all this hassle with changing his IP address and using a proxy? If this person is unscrupulous, he will find a way to cause trouble or something similar.
My post simply showed my current position. Of course, he can do what he did again, only more carefully. And it's online, not offline... It's harder to catch him there.
P.S. Of course, you can put him under strict control, so that he reports all his actions, battles, and makes corresponding saves... But we don't have cameras in his house, do we? Previously convicted criminals commit crimes again, only more organized, taking into account the mistakes of the past