There is nothing dishonest about putting extra people in a room unless it is a breakfast situation as EJB said
I disagree. Sometimes it could be a fire-code related issue, sometimes it could be taking potential money away from the hotel. I would think it's a similar situation to illegally downloading, switching seats at a ballgame etc - you're taking a potential revenue stream away from a business, especially if you otherwise would have bought 2 rooms. I think its somewhat of a gray area both ethically and Halachicly and different people and poskim might say different things.
In this case, I think OP would be fine on those fronts as he did ask permission. As a caution, I would still say not to broadcast it at checkin in case one agent happens to be in a bad mood etc.
