In college, I worked at a Marriott Hotel that was very well run. I mostly was a bellman/airport van driver, but from time to time I pitched in with housekeeping assistance on convention weeks.
I can remember in initial housekeeping training the executive housekeeper telling us all sternly that, "If any of you are caught washing glasses in the rooms, that is grounds for immediate termination."
As a housekeeper, of course, that was much easier than the alternative, which was to pull from new glass inventory which had to be carried from the basement of the hotel to each floor and then managed from the cart. Sounds easy, but it really can be a major pain.
So, I understand why so many housekeeping folks want to skirt the responsibility of using newly washed glasses, but the reality is that in every county in the USA, it is a significant violation of health code to ever present a piece of glassware for customer use that has not been through a santizing wash.
Case closed.
If you are at a hotel where you suspect (or in this case, KNOW) that the staff is choosing not to give you clean glasses, do us all a favor and let the GM know --- not the director of housekeeping.