This is a tough one. I'm not a lawyer, but here's my take on it. If you rear-ended the person, it's probably your fault legally. Even if it was the other dude's fault for an illegal lane change. I had a guy slam on his brakes in the middle of the road once; I hit him - My fault. My insurance company said it wasn't and they hated these situations becasue they had to go by state law which says all rear-ends in Maryland are the fault of the person who hits the other guy.
If he were to have sideswiped you, you'd have a good argument for it not being your fault. "Failure to yeild right-of-way" is the trick for this not being your fault.
I wonder if they would care that you locked up the tires on purpose and thus avoided the ABS - that doesn't look favorable either. Just a thought though. On the other hand, it does show you tried to stop. Did you leave skid marks?
A tip for all of the kids out there - ALWAYS get a police report if you are unsure of whos fault it is or if you are sure that it is someone elses fault. The amount of damage is irrelevant - there is no minimum to file a police report on the scene.