Bob: how are you getting home? Jane: I have to catch the bus home Bob: I'm leaving now, and I can give you a lift home. (I can drive you home) Jane: but my house is so far away! I don't want to inconvenience you Bob: it's ok, I have to drive past your suburb on my way home tonight Jane: Are you sure it is not out of your way to drop me? Bob: no problems! It's not far out of my way, it will only be a 5 minute detour for me. (Bob will not have to make a very long detour, so it is "not out of his way")

Gavin's example is exactly how it would be used. But to summarise: Are you certain that you will not need to detour too far, in order to take me (there).

Are you sure it is not out of your way to drop me OFF?