First of all let me thanks to Jovoto and Beta Cup for initiating such competition, the thought itself is a great step for awareness.
We talk on recycle-reuse-eco friendly and so on and we do put efforts for it but difficult to regulate practically when things are global. So here in this option �Resize� I do suggest small change, make the cup size half, if we consider it than all the problems, expenses, usage, consumption etc. will be half. It has limitation of takeaway option but at coffee shop you can use such cup and drink coffee as may time you wish of course by reusing your own cup on same time.