If its true this has got to be a good idea to stop all the people who think they can just use the same mug for life

Disney have applied for a patent 'Self-Service Beverage and Snack Dispensing Using Identity-Based Access Control’ system. This system will close the loophole of re-using mugs from previous visits as you will probably need to use your room key card and finger scan as you do with park ticket to get re-fills. Snack vending machines using DDP snack credits are also planned.