Drivers do not need to log out of the mobile app to leave it.

When drivers need to use they phone for something else, they should just use the Home button on the iPhone or Android to leave the app and go to the Home screen. The only time they would need to actually log out (by selecting Logout from the menu) is if they were sharing a phone with another driver and they needed to switch who was the logged-in user, or if they want to clear their list of past delivery receipts.