This has been a bug for a while, but if anyone with edit perms grabs an object with keyframe motion - it freezes visually but it continues applying its last impulse on a target (at least avatar, I haven't tested on physical prims).

I basically have a trampoline which quickly goes up 2m on collision. If the object is being edited (by anyone with edit rights), and someone collides with it, they are pushed upward until they stop editing it.