That's what I do. If I pay for a room, and reserve it for X number of people... what difference does it make if they stay there or not. If the rate for 1 is the same as two in the OP's case... make sure to always reserve for 2.
Originally Posted by
londonienne
While it's possibly morally questionable to do so, and I haven't done it (yet) myself, I would recommend booking a room for 2 people in the first place, as there never an extra charge for that. Then feel free to bring along anyone that you wish.