Does calling startserviceatexact guarantee the service will run around that time, despite that time being long (eg. 3 days from now), or some other things in system other than force stop can cause the scheduled service to be cancelled?
It will be canceled if the device is rebooted. This means that you need to also have a service (not the starter service) that is set to start at boot and reschedule it.
It might also be canceled if the app is explicitly killed by the user.
So it won't get canceled no matter what (eg. device RAM is overloaded by other apps, or other apps scheduling too many alarms, etc) even if the alarm is days away, if the device is not rebooted and the app is not killed by the user, right?