I find that it's hit or miss whether or not the hotel dryer has a diffuser. I think it really depends on how old the dryer is and how many opportunities there have been for the diffuser to get misplaced. I recently stayed in a newly renovated room and was the first person to use the hair dryer so it did have the diffuser, but often they are missing. I have tried bringing my own but it usually doesn't fit on the provided dryer. The hair dryers in the rooms are always Conair. I don't buy those at home. I have a professional grade hair dryer. If you do have a Conair at home, yours might fit the room dryer since it would be the same brand. I now lug my own dryer unless I know the room is very recently updated. It's huge and heavy but I can't do my hair without the diffuser.
EDITED:
SOOO- I just wrote this whole thing and now I realize I'm actually talking about the CONCENTRATOR not a diffuser.
Sorry OP!
I'm leaving this here on the off chance that you actually meant the concentrator too

