Did they say if they were staying in the DVC section using / renting points? If so then I have read at a DVC property they only do housekeeping every x # of days. Not sure about regular rooms at Poly but can't believe they are different from our experiences at POFQ. We leave used towels on the bathtub and find they are replaced. If we decide to reuse towels we leave it hanging on the door or towel holder.
The other possibility was the poster opted out of housekeeping for the gift card offer.
Towels are replaced daily if you have housekeeping daily.
I believe BEDDING for anyone is only replaced every 4 days.
I'm unaware of what DVC does but I don't think they have housekeeping every day so I could see towels not being replaced daily.
With a reservation through DVC, if you are staying seven nights or less, on day four (day one is check in day) you will get your trash removed, towels replaced and amenities replaced. No vacuuming, no bed making or linen changing. If you stay eight nights or more, you get a full cleaning on day four and on day eight you get trash and towel service. Then the cycle repeats.