The interesting thing I learned about this is that the big names in chess all agree that they don't need to be told what move to make. In a recent interview Magnus Carlsen said:

> The people who get caught are those who cheat in a really obvious and stupid manner. The problem was that he [i.e., a player caught in 2016] was not good enough to see what would’ve made sense.

> Had I started cheating in a clever manner, I am convinced no one would notice. I would’ve just needed to cheat one or two times during the match, and I would not even need to be given moves, just the answer on which move was way better. Or, here there is a possibility of winning, and here you need to be more careful. That is all I would need in order to be almost invincible, which does frighten me.

So all you need is a buzz or maybe two - "caution" and "opportunity," "defense" and "offense" or whatever.

The difficult part is getting the game state to the device. In streamed games this can be done with a medium amount of trouble but in non-streamed OTB games you'd need the player or a confederate to be silently inputting moves for the engine to respond to. Not impossible but... difficult. Nevertheless, when the prizes are in the hundreds of thousands, people may try to find a way.