I think the real error is caring so much about one game that both players feel they have to do one thing or another so that they don't lose rating points.
For one thing, a rating is a statistical average. If you really deserve a higher rating, it will happen. If you really deserve a lower rating, that will happen, too. More importantly, people get too wrapped up in it.
For what it's worth, if I stumble into a win because of an obvious mouse slip, I would offer the draw. If someone didn't do that for me, I wouldn't care. It's just a game. In an OTB game, I would definitely give the player the benefit of the doubt if he claimed to have made an accidental move. Unless I had strong reason to believe he was trying to pull a fast one, I would let him make the move he intended.
As for OTB games, the rule is quite clear that an incidental touch does not compel the player to make a move with the touched piece. However, if the touch could reasonably be considered intentional, the TD is to assume that it was intentional, and force the player to make the move. The examples given in the rulebook are brushing the top of a king while reaching for another piece, or using one's pinky to move a piece toward the center of the square without saying "j'adoube". In such cases, the TD is to assume that the touch was not deliberate and that the touch move rule is not invoked. On the other hand, if the piece is grabbed with the fingers, but then the opponent claims it was his attention to adjust the piece, the TD is not to believe him, and instead force him to make a move with the piece.
Ah yes...the almighty rating points! More powerful than superman, more alluring than Halle Barry, more intoxicating then crack, the things we will post, the accusations we will make all in the name of the almighty rating points.
I give take backs if it's an obvious mouse-slip. Heck I'll even wait for a while to give them the chance to ask for a take back.
But when I slip up I don't except it, I wait for them to make their move and then I'll resign. No hard feelings.
If they've been a jerk, I'm no mother Teresa, I'll decline a take back request... that is if they're fast enough to ask for it before I pounce on that piece they just dropped