I've done some research about this issue some time ago, so I can share some info with you. The main problem here is CSGO being free to play. You can create as many accounts as you want, and play... or just authenticate and keep some communication beetween Steam+game server.
The author of this hmm lets say "solution" is well known sourcemod coder from Ukraine.
Valve needs to update their master servers algoritms for CSGO. One idea I have is just adding extra IP check to know how many accounts are connected from the same IP to the server.
EDIT: Easier solution for Valve - checking if VAC is really enabled on server.
What you all can do to fight this is sending e-mails to Valve/CSGO developers, and maybe one daythere will fix this. In my opinion making this more public can also help, because at some point they will have to do something with this.
* if I've shared to much info, pleas edit my post and remove this part. I've never used this on any server.
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