New bones added to existing skeleton

If I have a rigged model, and I bring in an animation with the same bone hierarchy as that rig.. but with an additional number of bones. As far as I can tell Unity simply ignores the new bones as long as they dont affect the original hierarchy. I did a test already where I added a bunch of bones to the world bone of an existing rig.. and when I brought in the animation it seemed to import fine.

I guess I just think its too good to be true, haha. Can anyone verify that adding bones to newly imported anims, as long as they dont affect the original heiarchy are simply ignored?