I wonder what the ratio of small illegitimate charges is to errors in the hotel's favor? My guess would be that the former out number the latter by many fold.

Your question seems odd to me. Are you saying that that "it all evens out"and so it is OK? Or that some people not correcting errors in their favor excuses what seems to be common "error" in favor of the hotels?

With respect to the OP, I wonder if we might also include this question:

How many times have you found errors in the hotel's favor and how many times have you found and error in your favor?

I, too, have been charged for minibar/pay per view not used several times. I have never had an error in my favor on a hotel bill.

I do check my bill at check out time and so far have met no resistance to getting a very quick removal of incorrect charges.

The one time I could not achieve this was when I was charged for dinner for two at the Marriot in Zürich. My wife and I had not set foot in their restaurant .. I forget the name. We were checking out with a fairly long line behind us. The desk clerk said that we would have to wait until she cleared the line before she could get the check from the restaurant which, according to her, would certainly bear my signature. In other words she accused me of lying to her and of trying to steal two meals.

I could not wait nor could I deal with the manager as shuttle to the airport was about to leave. Unfortunately, jet lag and the crush of six weeks of accumulated mail contributed to me forgetting all about this until many months later and I did not contact my cc company.

I have not contacted the Marriot for further stays either.