I presume "whomever they wish" means anyone who is not a cheater. In that case they need a whitelist. Because without one, every player is a potential cheater. Non-whitelist solutions don't match what I presume they want. They asked for NotCheater, server returned MaybeCheater.

Without a whitelist, it's only a matter of time before an actual cheater joins their server and ruins their fun.

Enumerating badness just doesn't work.