I remember I made this same thing when I was in undergrad b/c my uni didn't have waitlists. So people could waitlist on my app. Their priority in the waitlist is determined by a market. I remember getting SMS's in the middle of the night alerting me that a seat opened up!
"Their priority in the waitlist is determined by a market." I'm very surprised registration systems aren't (generally) some kind of phased auction. There's got be some research, experiments somewhere exploring different strategies. I worked on student facing software in higher ed. Admins were obsessed with fairness. Our registration systems had all sorts of arcane rules. Which were hard to explain, validate, troubles…
http://www.thecrimson.com/admissions/article/2013/9/10/cours...