[Ekaros]

Maybe then we should increase security level in these events. Demand all the players to be naked, in locked rooms. With full body cavity search. Just to exclude any possibility. Do not them leave until game is over. Bucket can be provided if needed...

[FartyMcFarter]

The room also needs to be a Faraday cage, in case a player has a radio device implanted under the skin, or swallowed one.

Don't forget soundproofing to prevent communication via noises. Oh, and enough earthquake proofing to prevent communication via vibrations.