Just to make sure I understand you, are you saying that I should create a small dummy service in my app, that hopefully will always be running (via "run at boot"), and when the user goes to uninstall my app, the service_destroy event will be triggered and can then prompt the user to restore the default ringtone?
If so, I can give this a try, but I hope the system/homescreen uninstaller doesn't force a kill task on the entire service and prevent my app from displaying a prompt to the user midway during the uninstall process.