Never seen one with mold... a few times I have to clean the unit as opposed to the carafe or bucket. Rarely it's bad enough that I have to call housekeeping to exchange for a clean one, but it happens.
To each their own, and I would know the difference between a 50 year old scotch and one from a box (or a whiskey), but I sure know my coffee and I need a maker/kettle in my hotel room.