I have heard of others talking about leaving their luggage outside at POR. We did POR both times before our cruise and they made it very clear that we should NOT leave our luggage outside.
We were told to have our luggage all packed and just inside the door. The came early the next morning (I think around 7 to 8am) to pick up the luggage.
One time we had gotten up early and already left to room for breakfast, they just came in and got the luggage. The other time we were still in bed, they knocked, we said come in and they got they grabbed the luggage and were gone in less than a minute.
Have everything packed with the luggage tags on it. To be on the safe side, have your carry-on luggage way back in the room, no where near your other luggage so they don't grab it by mistake.