My significant others and I never had an issue checking in. We just asked for a room with a king bed. A few eyebrows raised, but we weren't charged extra or questioned about three people in the room.
ETA: If you ever choose to vacation in Savannah, GA, I highly reccomend the Mulberry. http://www.savannahhotel.com/
(And if you want to stick to "branded" hotels, they are affiliated with Holiday Inn, so you can use/collect rewards there.)