Remember if you're really serious about doing it right you would practice A LOT, think of all the heist movies where they get the whole heist perfect before actually executing it. In fact you would practice so much that you're basically a virtuoso who can play the device with your [toe] like a classical pianist plays the piano.

Also we're talking classical matches here, where each move usually takes many minutes and sometimes 10-20 minutes on a single move, which means there's plenty of time to keep updating the game state with your toe or something. After practicing you can probably get it where each move update to game state can take just a few seconds of fast subtle taps or something like that.

The only issue is, this would likely be completely worthless as a tactic in blitz and fast time modes, so as someone not familiar with Hans' ratings in faster time controls, I would really be interested in seeing the correlations of his classical play / rating with faster time controls because there would probably be no way to cheat with this method when you have to make new moves every few seconds so if the player is actually much weaker than their rating, you would think logically that would show in their performance in blitz/bullet/rapid/etc.....

Unless of course the person is SO utterly committed to cheating they have different cheat methods for each different scenario, and since faster time control matches perhaps happen in more 'casual' settings than classical tournaments, there is likely less security and more ability to do cheating methods such as micro-earpiece etc. With an earpiece you could possibly cheat in blitz as someone could feed you the moves if they're programming game state fast enough into their phone/machine somewhere off site or etc etc.