No Freindly collisions is a good idea, and is similar in vien to the reason for freindly fire. You don't have freindlies shooting each other down because of Kill SHooter, if freindly collisions were available then they dweebs would just ram ya instead of shooting.
I for one hate kill shooter and would like to see it go away. Null the effect of the fire, but don't kill for someone else flying in front of you.
My $.02