Now, it's Apple's choice whether to make that refund, and it seems a tad unlikely that they'd do it for no good reason, but 90 days is a long time for some of the apps in the app store to remain useful to users. And let's face it: there's no small amount of people out there who are happy to save money at others' expense.
How realistic the danger is remains to be seen, and the fact is that it's part of the price of doing business in the App Store.