Chess is, in a way, doomed. At this point cheating by a smart perpetrator is nearly impossible to detect.
- Miniature devices can even be implanted. You can probably already have a chess engine onboard your body.
- Accomplices of a cheater only need to transmit a few bits of information to be useful - making cheating cheap when audience is allowed.
- Statistical methods will not be able to detect a player increasing their apparent skill by a small margin (help with occasional moves, successively picking suggestions from a varied group of chess engines so that adherence to one engine cannot be proven)
Given this, we will be left with cheaters getting caught rarely through obvious slips in op-sec (device falls out, gets picked by a detector through unlucky occurrence)
or
We will be forever accusing people of cheating. They will deny it. We will ask them to explain why they made certain moves. They will fail to explain themselves sufficiently... Are we here yet?
You could play in a Faraday cage, use an SDR and check for weird radio signals, and other steps. Some of this would only really be feasible at the highest levels, but that's where going to those lengths is needed.
This seems like an overreaction. We regularly use scanners to detect foreign or hidden objects on people, such as at airport security. It's not out of the question to use such approaches at high level chess where the cost/benefit is worth it.
Airport security is trying to find bombs and knives. Those are potentially orders of magnitudes bigger than the cheating devices we're talking about here.
Airport security won't find my 0.1mm knife, and it's not a problem if they don't.
Given this, we will be left with cheaters getting caught rarely through obvious slips in op-sec (device falls out, gets picked by a detector through unlucky occurrence)
or
We will be forever accusing people of cheating. They will deny it. We will ask them to explain why they made certain moves. They will fail to explain themselves sufficiently... Are we here yet?