I feel like Magnus is reasonably justified regardless. He might not have actual proof of Hans cheating OTB, but he probably was reasonably aware of the repeated cheating online. And then he played a game against Hans OTB where Hans made some strange moves that seem more like engine moves rather than human moves(given Hans rating). I feel like that was enough to create a situation where Magnus is reasonably justified in pulling out of that tournament. Even if he can't prove what happened in the OTB game and even if Hans wasn't actually cheating in the OTB game, I don't blame Magnus for not wanting to play against Hans. He is already suspicious of Hans going into the match given the online history, and then had a weird match OTB...