Uhhhhhhhhhhhhhhhh, call the rental company? What would you expect them to do? It's not illegal, against any rules I know of, or dangerous.
Maybe dial 1-800- prudish
In the tub, it's ok and legal. Outside of the tub it is verbotten to have exposed genitalia, anywhere. Private property or not, if anybody else can see you, it will draw a ticket.
If I had a young daughter that witnessed this, I'd be the one in the back seat of the cruiser. The naked men would be the ones in the back of the rescue squad vehicle!
Walk over the next time you see them...Not in the tub....And ask them to wear a suit in public.