I think more and more people are realising they can get a refund and still keep and use the App, I have seen a rise in this in the past few years too. I haven't had much luck in finding out how to check if a user has had a refund... you can for in app purchases, just not for the app itself.

Did you find an answer on this? I'm concerned that more and more people are realising that they can get a refund and still keep the App. Apple still keep their percentage, so it is very disheartening to think people are doing this. I can only find answers relating to in app purchases, not refunds on the paid App itself.