Was at a basketball game today and they the system there. It's really neat to watch but the cup needs work.
It's done with a magnetic disk that seals over a washer around the hole at the bottom of the cup.
If you touch the bottom of the cup, you break the seal...not good. My friend inadvertently put his baby finger under the cup and half the beer came out. Got his shoes but not his clothes. And even if you do keep your fingers off it, there is a problem with seepage.
It defiantly has potential. It save time and they will sell the disk space to advertisers, but they have to get a tighter seal.