Earlier quoted context omitted.
That's true; that would be the better solution. Requesting a refund before deleting the app would give the user an error message telling them to delete it.
With the corner case that if the user no longer has access to a device with the app installed, they cannot get a refund.
And doesn't apple have some form of remote logout/factory reset feature for lost devices?
EDIT: (Sure requiring remote factory reset for lost devices would not work if it's a iPad which has not internet connection and never gets one again in it's live time, but that would be an acceptable corner case I thing).