So, because a certain rule isn't enforced 100% of the time on 100% of the ships, it's okay to ignore? The OP was looking for guidance on getting a scooter with her interior cabin. I would never advise anyone to simply disregard a written policy, especially when the safety of other passengers is involved.
And I would certainly not be shy about reporting scooters left in the hallway for an extended amount of time to ship security. The first time I saw it, I might give the person a little grace and assume that they had just popped into their cabin for a few minutes, but after that, maybe not.