I remember an article at WSJ years ago on how many startup founders choose such tongue in cheek / humorous names and how that is almost always a bad choice. But calling this airmule is insane.

On the risks, I wonder if making the person carrying an extra bag the temporary owner of it (and showing him the packing of the luggage) so he can always say no would help making it safer for the user. But I personally would never do this even in this setup.