HAL has size limits on their site for all handicap equipment. If everyone abides by the rules there is plenty of room in the hallways. I am currently on the Westerdam and the room steward has urged me to leave the scooter out since it is so difficult to get into the cabin. As I said originally it is very small and only weighs 47 pounds.
If I leave it out it is for a short period of time, not hours.