couple of good ideas there.
@1- I for one would keep my older vintage cups, other people probably would jump on the deal!
#2- Bar code is a good idea, biggest problem would make one that is wash resistant for a year.?
Maybe they could scan you SP or entry ticket.. same idea- 1 refill per hour per pass,
BUT that would not eliminate "sharing" the cup between 2 or 3 people, which would be cheating or actually stealing...