Ever gone to get a pool towel only to find out hey have not go enough yet? Have a look at the hotel balconies and you will see them fluttering tormentingly at you from afar.
Please if you use a pool towel return it at the end of the day for washing or you may end up the next day with out one.
Answer
Do the Pool towel run :- either upon returning late in the evening or early morning. Quickly run past all the balconies you can reach collecting up the towels and drop them in the return pile.
Same with the lounges - towels are deposited on these as the person goes for breakfast / out shopping for hours / or even back to bed!!! Scoop up the belongings & deposit these on the ground, grab a lounge at a safe distance or move the newly acquired lounge sit back and watch their faces as they look for theirs ....
Strange how this seems to stop the practice of towel & lounge hogs