Well to clear things up...
Me & Ronner made a Lua script that checks every entry on a server.
This means: We get the PBguid from the client and compare it with the list of pbguids on the server.
That list contains the pbguids of all registered crossfire members and is updated every X minutes by a cron Job (linux)
So when you are registered at crossfire you can play but you can only give in the pbguid after being registered for 14 days so it's easier to get the cheaters out.
If you see a hacker, we only have to ban his account on crossfire so the pbguidlist will remove his guid and so no entry for him for 2 weeks.
PBguid is the only 'non spoofable' thingie around (at least where i'm aware of) so the best method to keep things clean
This system sure has a lot of potential if we can make this standard... But i doubt that :)
Hope you get the point ;)
If you need more information, just pm me @ #crossfire (quakenet)
Cya,
Rfki