The integration is the hardest part of this idea. There are a couple of different ways to go and I'm still not sure exactly which is best. I'm debating between integration with other software suites, building a small POS layer or making it easy for courses to handle it manually themselves. I'd like to do one thing really well, but we may need to broaden our horizons a bit.

You're region is lucky then. In my region every course uses a different system.

I would use Clickpass on top of Open ID, Clickpass seems fairly easy to understand, even if you don't fully get all the details.