I understand the concern about the bags and not having a room number. It is not exactly the same circumstance but think about all the people who have a stateroom assigned and then check-in for that stateroom and then go one more step and go to the supervisor's desk to upgrade. It really is the bar code that matters, not the number written on the tag. Otherwise you would hear lots and lots of stories about how "we upgraded at the port but then had to hunt down our luggage".
Even if you have a cabin number and don't upgrade, sometimes things happen. One thing I've never had a problem with is luggage. Our worst experience was several years ago, on the first cruise after the re-imagining of the Magic. (Maybe other people's stories of misfortune will make you feel less stressed about your own? Maybe this will backfire and will just give you more to stress over but it has a happy ending!)
We checked in as normal, boarded when they called the first boarding group and went to upstairs (this was in Miami) to swipe our KTTW cards and board. Well, it was right at that swiping in when things really went awry. They called for a supervisor who came over, looked at the screen and then took our KTTW cards and asked us to step to the side. We were standing in that little spot, so close to boarding but not quite for over half an hour. All that time we just stood there watching hundreds of people board (yes, and getting looks from people like "what have you done wrong"). All that time, they never really told us what was happening, every once in a while someone would come over and ask who we were or why we were standing there. We would identify ourselves and they would nod their head like "oh yeah, you guys" and walk away. One person asked us why we didn't speak to one of the desk agents before we tried to board (when we said we had no idea what they were talking about and asked them to explain because they were treating us like we were trying to sneak onto the ship, they said they'd be right back and walked away.) Finally the original supervisor and someone from Guest Services came to us and told us the cabin we had - AND checked into, was not available - seemed they still had workers on board and one of them was in our cabin. They said it shouldn't have let us check-in so apparently they took our cabin out of service between the time we checked in and the time we tried to board. So we actually boarded the ship without a cabin assignment! As this was a two day cruise and we were scheduled for the next two sailings as well, we didn't want to be changing cabins every few days (they didn't think our original cabin would be available for the next sailings but thought it might for the 3rd; their intention was to find us a cabin after each cruise - when they knew if the workers would still be there or not and tell us when we checked in where we were going. So imagine having to pack after each of the cruises when you specifically planned to be in the same cabin so you didn't have to do just that; on top of then not knowing what cabin they were going to stick us in). So it took several hours with Guest Services to straighten it out and actually get our cabin assignment for the 3 cruises.
But I told you it had a happy ending. Just before the lifeboat drill, we were given a cabin - one we could stay in for all 3 cruises. It was still on deck 2 just further aft than we usually book. And even with all that mess, our luggage ended up showing up at the correct cabin door, just after the drill.