Allen,

I have never had a scope problem in Africa. But I have always used quick detachable mounts of some sort, and kept the scope in my carry on backpack I bring on the plane trip. Together with other fragile items such as my camara etc. Just incase the baggage monkeys at the airports decide to throw my guncase around as I'm sure some of them do.

Although I agree that bringing a spare is a good idea, I think the most reliable way to back up the scope is having open sights on the rifle. (Provided that the hunters eyes can use open sights)

Thus, since the open sights are always on the rifle, you can't leave them behind/forget them in camp/whatever, like you might do with a spare scope.

So the best solution IMO would be both open sights, and a spare scope.