I like this idea. A lot.
However,... I think there should only be a penelty for the HO, and not the others. All of the other "downers" are a natural part of this game, while the HO is well... grrrrrr.
I'm not sure how this would be coded though. Dmg is dmg to the server, and a collision isnt always a HO. I've had more than once an enemy plane run up my tailpipe while trying to get him to fly past me (likewise, I've done it to others).