So when it comes to things like this, the main considerations are accuracy in transmission and comprehension of the message.

Ah, I see. That's why the encoding you detailed in your previous reply is such.

making physical signals a far easier method of communicating “HELP!!!” than becoming a kegel master.

This made me laugh out loud. But yeah! I was so fixated on making a butt plug-mediated communications protocol that I overlooked a far low-tech, but more effective method. And if detection is a danger, the gestures used can be changed up and agreed upon before the match. One match might have massaging the forehead as the signal, another match could have scratching behind the right ear.

And my theory about the butt plug being able to be smuggled through a metal detector is not based in a proven fact, but rather the assertion that if you could get one through a metal detector, which may or may not be possible, there would be no other checks in place to prevent a player from entering a hall with one.

I see. So we're both coming from the assumption of "if it were possible, how might it go?"

More complex cheaters (who do not use an accomplice) have in the past gone to the washroom to find a stashed chess computer, plug in the position, see what the computer thinks, and come back.

Isn't this easy to catch though? Inspect the restrooms players have access to and periodically inspect them when no one's using it. Of course, this doesn't stop a determined cheater stashing a small device inside a pack of wet wipes, for example. Heck, if I were in that situation, I'd probably just stash a smartphone inside a supposed pack of wet wipes. It's boring, not as sensational as a butt plug for sure, but if it works, it works!