I recall from spy movies that disguises and distraction don't need to be perfect. They may only need to fool someone for a second. With that in mind, I can't think of a better place to hide a bone than out in the open where no one is looking for it. Good job Lucy.
By the way, a fourth Jason Bourne movie is being planned for release sometime in 2010. You can read more about this here. I'm looking forward to seeing it.