Ah. No. I wasn't very explicit. I'm tired and having trouble peicing legible sentences together.
By "messed with the first person's account" I meant what you already said, changed his account info, not done something like giving his stuff away. I'm just saying he should have done what he did, but ended it up with something like, "Ok, I've changed your password back. Let this be a lesson to you." Or perhaps reported him to Valve. That makes sense, too.