Whitelist Problem

We use the current Version of the Whitelist Script by Kanersps, but we noticed from time to time, that some people managed it to join the Server even when they are not whitelisted. The Server-console shows that they have the same SteamID as the last person who joined before. But that is not possible, so it must have something to do with the server or the script. @kanersps Maybe you can help me out.

Moved to the proper forums - read before posting please(!)