Back in the Dark Ages, I briefly worked at Round Table Pizza. I can't tell you how often folks would walk up to the drink display and ask, with no trace of irony, what sizes of drinks we had. Now, we had the drink display with the sizes and prices at eye level, so that when a person came up to the first place in line, they were a foot away, looking square at it. Yet, more often than not, I would get asked, "What size drinks do you have?" I usually brought my hand over and pointed to the drinks - "This is small... this is medium... this is large..." At that point, most of them had the good grace to look sheepish. They certainly couldn't accuse me of hiding that information.
I've found that most people, if they are anywhere where someone can serve them, leave their brains elsewhere.