score:7
To be sure, you should ask the resort, as this is a matter of policy for each resort/hotel, and there is no universal rule.
In general, I would expect there to be rules against taking hotel/resort property off the premises, but I would also expect that it is common to make exceptions if you were to ask--and possibly pay a deposit.
The other option is to just smuggle the towels away in your luggage, and plead ignorance in the extremely unlikely even that you are caught.
Just be prepared to pay for a replacement towel if the towel is damaged or lost while you have it away from your resort.