As far as I understand, “Permanent Ban” simply means that he cannot participate in tournaments.

Formally, it doesn’t even mean that. It simply indicates that instances of cheating have been confirmed for the player in question. Whether to accept him or not into a tournament is up to the organizer. However, the organizer will likely not accept him even if he believes the “Permanent Ban” is undeserved, because many players might simply refuse to participate in the tournament. But, in fact, the “Permanent Ban” itself doesn’t prohibit participation in any tournaments, as far as I understand.