What about if someone spins in front of you, does a full 360 and you hit them because they're far slower after the spin and there's nowhere to go? You get a 4x.
Or a car is rejoining the track and just pulls in front of you.
What about if you're in the middle of three cars, so car behind hits you, fine he gets a 4x, but now because of that you hit the car ahead, do you get a 4x for that?
And of course, 'strategic brake testing'...
The idea of altering the 'no-blame' system has been bandied around over the years, and maybe there is a solution or set of rules that would cover everything but I've not seen anyone come close yet, personally I'm far more willing to accept the 4x from a no-blame system than when the system decides the blame 'incorrectly' and I get the 4x from that.
I'm also of the opinion that almost all incidents can be avoided, and that over time the no-blame system works, a single 4x isn't an issue, especially with how easy it is to get/maintain an A-class licence, and if you're getting 4x's constantly then ultimately you should look at your actions, imo