I have first hand knowledge of one women who did it EVERY time she was onboard - my wife!!
Some cabins were OK while others were less than OK to say the least.
The best cruise for her was when i was on Sun Princess and we were on a 14 day Caribbean cruise. So as not to have to go through the ignominy of US Customs & Immigration in Miami, we were sailing out of Port Everglades at the time, she choose instead to embark in Willemstad in Curacao. She had arrived the night before and been collected by the ship's agent's 'mam' and taken to a reputable hotel. Then the next morning, in her own time, she was able to embark and settle in to my cabin, just behind the bridge with views out onto the bridge wings - but that's another story!
Anyway she made herself at home and, at sailing time, made her way up onto the upper deck to enjoy the delights of 'Sail away'.
During the day we had had a medical disembark, where the passenger was deemed to not be fit to sail by the local hospital, and the ship was informed mid afternoon.
After sailing and once all shell doors had been checked, i made my way to the bridge to collect the pilot to escort him from the ship once he had finished his duties.
When i got to the bridge the Captain called me over to one side and asked me if 'Mrs Holloway would like the use of a passenger cabin'? I said that she could 'force herself' if the opportunity was there, to which he offered her the medical disembarks cabin! Saying that if it was put back into passenger service there would be more complaints from passengers who 'knew they were entitled to it' than he was prepared to bother with!
The 'available' cabin was on the next deck down from my Security Officer's cabin, and right opposite a door that led to a crew staircase that led up to right opposite my cabin - now how convenient was that? It also has a small, but very nice balcony!
So i slept down there with 'one of the passengers' and returned to my cabin in the morning, via the 'walk of shame' in an 'acquired' bathrobe!
Sadly she had to 'slum it' for a couple of days on the next cruise back with me in my cabin, as 'her cabin' was allocated to a paying passenger!
The next cruise was exactly the same itinerary, so she disembarked in Willemstad late afternoon to catch her flight back to the UK later that evening.