Hah I will be going in 3 weeks for my first time ever in WDW and I will be buying the mugs for 2 reasons:
1) I need them at my stay there

2) I was also interested in these chips so I was planning on scanning them when I got home.
I actually used a what we call an Arduino board to create a Do It Yourself RFID Reader and wrote a custom app for it (I am a software Developer

).
The main reason I have this stuff is because years back my country introduced a RFID Card for Public Transport and scanned them for a hobby project...
Anyway I am interested in what way I could "hack" these things.
P.S. For the Record I do not plan on hacking the mugs for infinite refill I am interested in what way Disney use these chips cause I can see it's being used for a in between break but it is also an easy way to check the expiration date for these mugs.