So let me get this straight, you have never been rammed by an aircraft and thought it was his fault even though he didn't get a collision message?
I will defend this collision model too when an uninformed player begins whining about it but cmon, there are rare situations that do occur where fault is assessed opposite as to what really happened.
I haven't ever really thought it was the other guys "fault" only ever looked at it like it was either my fault or no one's. I see what you are trying to say though grizz but there are many times it is not anyone's fault.
I have had several near misses and if my adversary took damage because his computer "saw" a collision then it is on his end and if it was from a maneuver that I performed that appeared to me that I had room for then how can it be my fault that he fell to the ground or vice versa.
You can only base your decisions on the positions on your screen not on his so if no collision on your screen then there is no fault to you. Now in your example there is no fault you flew under a spit and he fell crashing to the ground, sounds to me like a no fault situation but non-the-less there was a collision on his computer and then things worked the way they should.
You obviously understand the collision model and like many of us feel it's the best possible solution but this is one of those things where sometimes there is no fault but action must still be taken.