Clever, but isn't there some danger that if you tipped it the wrong way when drinking out of it, even before the "gluttony" level, that you'd start up the siphon action, causing it to empty out onto the floor? At the very least you can imagine you'd get a bit of wine trapped in the curve, which would then drip out of the hole at the bottom.
I don't think so, because the column is in the middle; as long as the tube in the middle is narrow, whichever way you tilt it the height in the centre will be the same as it was at the start and nothing comes out. I guess if you tilt it past horizontal to drink out of while the cup's more than half full then you have a problem - but that sounds more like a feature than a bug.
Yes, upon seeing this I immediately wanted a 'trick' cup that did this but had this, umm, feature more hidden by placing it in the side of the cup not the middle. But then an unsuspecting, but non-greedy, user may spill the entire cup just by sipping out of the wrong side! The central column should make it quite safe in comparison.
