Living in Seattle I'm a pretty big Sounders fan, and building on this point, they have a pretty cool program started this year with their matchpass:
https://matchpass.soundersfc.com/
You get a card that has your season tickets in it and a bar code that gets scanned all over the stadium. You get points for attending matches and bonus points for various things like showing up early, buying concessions/merchandise, even watching away games on tv (they put a code on the screen you enter on the website). Discounts on beer/food until a half hour prior to kickoff further incentivize people to show up early, something our student section at least has a real hard time with. Then when you build up enough points you can redeem them for some pretty cool rewards, field level passes, player meet and greets, signed balls/jerseys, etc.
This seems like it would work really well for students and non-students alike, give points for attending non-revenue games, tie in with the book store for merch, and most of the rewards wouldn't really "cost" the program anything but some time.