Double dipping on vacation rentals?

[Delin W.]

I have both single family and vacation rentals. In my state (not sure if it applies to others), landlords are not allowed to double-dip. Example: Say the tenant's lease goes through the end of the month and they pay for that month then vacate on the 5th. I fill it on the 10th, so I would then return that tenant's pro-rated rent from the 10th to the end of that month. This has been my practice. 

I have also applied that to my vacation rentals, specifically in regard to cancellations. My cancellation policy is that if a guest cancels two months+ ahead of the booking, s/he gets 100% back. If s/he cancels 30 days+ ahead of the booking, s/he gets 50% back, but nothing back if s/he cancels less than 30 days before the booking. However, if the property gets re-booked, I always refund the guest for those days. I don't plan on changing this practice, because I think it's fair. 

I was following a thread in a vacation rental forum recently where the owners said they typically did not refund any amount, no matter if they re-booked the same dates or not. This sounds like double-dipping to me, but I couldn't find an answer as to whether the prohibition on double-dipping applies to vacation rentals or not. 

Again, I'm not changing my policy, but I am curious to know if it is allowed, since so many other owners appear to do business this way. 

TIA!