I think I found a way for cheaters to do it by wearing a headphone. But they are not actually listening to music. Instead, they are on hold with someone on the audience who can input the moves in a computer and will dictate the moves as the computer suggested. A lot of network providers offer unlimited minutes especially on weekends so I think this is highly plausible. Any recommendations how this can be prevented?
Something like this has almost certainly been tried before. See the Steve Rosenberg case in the attached article (some details of which are disputed by some of the actors):
washingtoncitypaper.com/arti … beside-me/
Speaking for myself, I police against this by asking to inspect odd stuff over or in players’ ears when necessary. I’ve only had to do this once, and it turned out to be plain foam earplugs. I was kind of embarassed.
I figured it out when I was running on the threadmill wearing my headphone and somebody called me. Apparently, I was not first genius to figure this out. LOL.
Are you referring to the big, bulky earphones or the tiny earbuds that people usually wear when listening to music? Hearing aid and other small receiving devices can be made small enough to be almost imperceptible except with close inspection. If it is possible to send a message or phone call through a big earphone, then that opens a real can of worms. Big events have rules on earphone/earbud use that might have to be changed; total bans may be necessary. Apple is working on technology to project images on the inside of eyeglasses similar to what the military uses.
I suspect that people who are sufficiently motivated to cheat will always find ways to do so.
This is one of the actors who dispute what McKenna reported. This Washington City Paper article had some bad misquotes in it. McKenna reported as fact something that another Arlington CC member had told him, that I had turned in Allen Cooley (1995) for cheating when I had not. One of Cooley’s rating victims noticed his own drop, asked for the crosstables and started the process. Admittedly I tried to investigate when suspecting fraud, but the USCF wouldn’t give me any information since I wasn’t directly involved. I told McKenna about the bad misquotes, asked for a retraction and it went ignored. If you want the story from my perspective, it appeared in Chess Life March 2007: uschess.org/content/view/101/77/
One interesting fact that didn’t appear in either article was that there was a Soccer World Cup match appearing on TV several floors below the playing room. Every time a great play was made the ruffled roars were heard in the playing hall. Sevilla noticed that with each roar, his opponent grimaced or made a painful expression. What that told me after the fact was that his accomplice had been sitting in that crowd of very loud cheering people and the noise probably flooded the Phonito device…
The following year Bill Goichberg introduced a machine that scanned for radio waves but it wasn’t a very advanced model. Several months later at the US Open in NJ, a former military intelligence officer told me of a larger and better device that would not only detect the waves but allow you to listen in to what was being said… “Nf6” 
I keep waiting to see a bump in someones neck, the Rybka Implant…
Resistance is futile.
Jon Luc would disagree, strongly 
There have been rumors for years of radio receivers in tooth implants.
I saw a recent interview with Lucille Ball in which she talked about her experiences with this during WWII. She reported getting Japanese messages through a new filling, and it was true - a spy cell was in her building and was arrested. Apparently with the tooth filling and repairs she had, it could act as a receiver for morse code for several months until the filling started to degrade. Whether a chess chip could be installed in a tooth is another matter, but if your opponent has a tooth camera - beware!
In 2015, glasses or goggle type “computer” glasses are
available with the screen on the eye piece, so that a cheater can
see fritz playing his game.
What should the reaction of the TD be who is asked to inspect such
glasses for this technology?? What if the “cheater” complains about
a “gross breach” of his privacy??
Rob Jones
Here’s a report on cheating at a chess tournament in Ireland: