Something to consider is that hotels are simply trying to look out for their guests and not dictate who should sleep with who. For every guest that is offended by this there are many guests that are angry that they are forced to sleep in the same bed with their business partner. It would probably surprise you that some of these same business people are actually offended when the suggestion of one bed is made. Not right but it happens. So maybe they think a mistake has been made. The best way to deal with this is for them to say "I see you booked a Kingsize bed, what did you prefer?"
The best line is when the gay desk clerk is selecting bedding type and says to both "Two queens?"