Jon Jacobs sends in a link to the online version of an anti-cheating petition he helped organize and send to the USCF. More than anything it's a flare and a call to action regarding the potential for cheating at open events with big prize funds. One incident mentioned in the petition was covered here. (Links to the HB rules were dug up by Duif here.)
Cheating has recently been in the news at the top level as well, when one of the San Luis FIDE WCh players hinted that Topalov might have been aided by a spectator with access to a computer. Kasimdzhanov's similarly themed comments in the latest New In Chess leave seem to finger him as the one involved. His comments in NIC only mention that the conditions in San Luis made such a thing possible, but it's not hard to imagine a listener running such statements into an accusation.
I seriously doubt a pro with much riding on his reputation would risk trying to get assistance, at least not at the top where reputation means invitations. (I'm talking OTB here; even strong GMs have been nabbed listening to Fritzy during online tournaments.) When it comes to amateurs playing for big prizes, that's a different matter, which is why the petition's talk of penalties is so relevant. With consumer electronics getting smaller and faster, having a hall full of players with nothing to lose and thousands of dollars to gain is unattractive.
So far this sort of thing has been left up to the organizers. We know about Ponomariov's cell-phone forfeit, but the same rules aren't universally applied. Having your phone go off shouldn't be treated the same as being caught in the bathroom stall running Fritz. Being caught cheating should result in a serious penalty by the federation, not just the loss of a game. Conclusive evidence will be hard to come by, one of the things that makes it tempting. But a watch list is certainly a good start.
An ounce of prevention being worth a pound of cure, we need some ideas about how to control the playing environment without turning the hall into a prison. Checking all electronics at the door is not very practical, unfortunately. Prohibiting spectators is a drag, as is forbidding the players from leaving the hall, or only using one or two authorized restrooms. So deterrence may be the best solution and that means a coherent penalty system that is actually implemented. Are there any federations that have policies about this?