Sorry if this has already been asked and answered, I didn't read through all the pages.
Just checked in for a 17-day reservation and bought two length-of-stay mugs. After the purchase, I asked the cashier if the system pulled my stay length from the reservation, and he said no, it would be active for 14 days. When I told him our reservation was for 17 days, he said I'd have to purchase additional days if I wanted more than 14 days.
This led to a conversation that became circular very fast. I told him the sign doesn't say 14 days, it says "length of stay." I wasn't going to pay for any additional days, as I'd already purchased 17 days of mug use for a 17-day reservation. This led right back to him saying it was only good for 14 days.
This conversation was at Saratoga Springs' Paddock Pool Grill. I plan to ask about it again next time at Artist's Palette and can ask a manager to explain it to me.
Anyone else had a mug for a longer reservation? Did you find this to be your experience, or did they honor the full length of stay? I'm not sure if this is a case of an uninformed cast member, or of Disney not honoring what was advertised.