Just responding to the last one, it was that easy and that's why nowadays the entire premises is swept for any potential aids before the tournament (I.e. the day before, go through every space and make sure that nothing is hidden), the player bathrooms are separate from everyone else's so that no one can sneak in to place something there without going through player screening, and everything you carry into the match is thoroughly inspected to ensure it doesn't contain a chess computer (to the point where they will check people's lipstick).

The reason the butt plug theory gained so much traction is that with the current security, there's only one check to stop it (the metal detector), the cheating method itself is theoretically sound, and its attention grabbing enough as a concept.

Much as with anything competitive, it's an arms race to gain a leg up before the advantage is neutralized so I'm sure that someday we will see a genuine case of butt plug cheating or security measures put in place to specifically prevent anally assisted gameplay