my app online has been purchased and downloaded only a couple of times but one guy cancelled after having the app delivered. and google checkout refunded him. I really doubt he deleted the app. As a devoloper do we have any leverage to stop people from downloading an app then asking for a refund. I don't think there is any way to garranty that no longer have access to it unless they willingly uninstall which they might not.

I have had this happen twice on one of my apps when I first put it into Google Play. I complained to Google Checkout and they were adamant it was a technical problem and that the user had been unable to download the app due to a technical glitch. The net effect is a lost sale no matter what the reason, but Google just said sorry and they were trying to fix the problem.