Well the best way for Hans to prove he didn’t cheat is to give amazing analysis after the game demonstrating his super-elite chess thinking. Unfortunately, he often sounds like someone who did nothing on a group project trying to explain how it works to the professor.

I know this isn’t proof he cheated, but it doesn’t do him any favors when he’s already under suspicion.

Edit: Way back, decades ago, in Warcraft 2, I became strong enough to regularly get accused of cheating by people who weren’t familiar with me. However the converse side of this is I was extremely accurate at detecting actual cheating.