I myself have a WDW trip coming up in just 29 days, and I am still deciding if I want to purchase the refillable mug. In the past, I have been able to use them at other hotel food courts. For instance, I stayed at Pop Century in 2009, and one morning, I ate breakfast at the food court at Pop. I had my mug with me, and I boarded the bus for the Magic Kingdom, right after breakfast. Later in the day, I had dinner in the Contemporary restaurant, where they sell the mugs. I used my mug with no problem. Not sure if I can do that with the new system.