Situation:
An enemy Poe has one health left. A Sigma Squadron Phantom at range 2 fires at it and rolls 3 blanks and a focus. >I don't have a focus token<.
He rolls defense dice and blanks. Either assuming that I had a focus, or mistakenly believing that my roll had a hit in it (I rolled into a dice tray and maybe he just glanced into it and didn't bother to double check), he gets rather angry at his dice and removes his Poe from the board. He is not aware that he did this until I told him after the game, and he said he could have sworn there was a hit in the roll.
I say nothing because I need to win at all costs. Did I cheat by allowing my opponent to do something that's not allowed? He did kind of intentionally ruin the game state on his own, the punishment for that should be not allowing the placement of the ship back on the board.