Then next question.buzz said:Yup.

The player knows I've been keeping track of the modifiers on him, so he hasn't been. He's pretty sure I messed up. But he isn't totally sure. He doesn't ask me to recalculate, but he probably would have if I'd erred the other direction, and hit him when he thinks he shouldn't have been hit.
Is HE cheating?

This is how I see "cheating" issues come up in real gameplay. I've only met one or two actual, intentional, knowing and malicious cheaters in my years as a gamer. I've met a lot of people who just kind of... let things slide when they think they're going their way.