And Groupon changed their refund policy...used to be if you didn't use a Groupon (so long as it wasn't a dated event) you could ask for a credit to your Groupon account.....now you have 3 days after purchase to request a refund. After that it's a final purchase.
I'd contact the balloon folks and ask them what happens if weather cancels and you can't reschedule because you're going home soon. Perhaps they can extend it (in writing!) for your next trip?