This might be very simple and I just didn't run across the right example script or forum post (it's hard to search for), but:
How can I detect when someone has right clicked my physical object, stopping it dead in its tracks?
Detecting the velocity going to zero won't do, because this object is going to hit and bounce off things a lot anyway.
I know this is possible because the "Lunar Lander" game does it to prevent cheating.