My experience with this is on NCL, not RCI.
During one slot pull, I hit a $1200 win. Because I'm from the UK, there was no tax to pay on the winnings, but the casino staff made damn sure that I was from the UK, and that it was me who pressed the button - had to retrieve my passport from the cabin, and saw them checking CCTV as well to make sure it was me who pressed it.