[tremon]

It's not hard to maintain a safe following distance.

So if a car swerves into your lane 10 meters in front of you, then slams on the brakes, you're at fault because it should have been so easy to maintain a safe following distance? (This isn't hypothetical, I've had this exact scenario happen multiple times -- on/off ramps seem to bring out the worst in some drivers).

[frumper]

I don't think anyone is saying what you're suggesting. If you're following a car and they stop, you should be able to stop as well. If a car pulls in front of you and slams on your brakes then that is quite a different scenario.