What counter-measures for cheating exist? Given how huge an advantage real-time external feedback to a player during championship games would give the player, do any of the major chess championships deploy counter-measures to prevent the same sort of cheats you might expect to find at a casino? If so, are these counter-measures well known?
There have been tournaments that require the players pass through a metal detector, and play in an isolated environment with no spectator contact.  Still, there was the whole Toiletgate incident during the 2006 Topalov-Kramnik match, so even these measures might not seem like 'enough.'  Besides resorting to strip searching the players, what else can be done except isolate them from the outside world during the games?