I believe it was more like: a guy was accused of cheating (against Magnus Carlsen), and anarchychess on reddit came up with the buttplug theory. Now everyone thinks it actually happened.
Considering that you can control Lovense toys (and others) from any where in the world, if they had no delay in the live feed, it would be simple to communicate moves, even to a complete novice.
From there, all you’d need is somebody in the audience with a chess game open and set to the highest difficulty.
That person “plays” as magnus and sends the moves the AI takes.
The easiest way to prevent it is to prevent people in the live audience from having phones, and delaying the feed ~5 minutes for everyone else.
which is normal, actually, since you want to cut the feed before a streaker… oh right this is chess.)