> Or that parents could use a Uni subscription card that allows for purchases from the campus grocery store and the bookshop to be capped at a reasonable rate
A bunch of unis already have this model and their own card for it, and even extend purchases to local businesses
It is the control mechanisms that make it interesting, not just the group of retailers and funding source.
With the control mechanisms you have the basis of a food subscription, a book subscription... allowances for very specific purposes at a rate that is pre-determined and could be set per retailer or even for specific products if such integration were achieved.
This is what makes it more interesting than any pre-paid card or coupon system.
A bunch of unis already have this model and their own card for it, and even extend purchases to local businesses
e.g. http://bluebucks.umich.edu/p/home.html