[GuidoK]

^and that is the problem.
A GTR is obviously much faster than that clio, and taking a corner at a certain speed might be very slow for a gtr, but very fast for the clio and thus having to steer towards the apex.

But still normal road rules apply, and that means that you cannot swerve from one side to another while being overtaken.

It's a very delicate balance, and because the track is very narrow/curvy, crowded, long (not easy to learn), full of blind corners/blind bumps, and novice and expert, fast and slow all drive at the same time, it's dangerous.
You constantly have to be on your qui-vive and aware of the cars around you.

Maybe to prevent this one could make the rule that you cannot overtake in or in the vicinity of corners. But with 73 corners or so that takes up pretty much the whole circuit (and when is it a corner and when not).

I'm guessing that on the current ruleset a lot of people with a hell of a lot of experience have thought a long long time.

That's why almost all insurance companies have stated in their fine printing that crashes on the ring are excluded of damage payout...
At least in Europe.
That's why who is to blame is of less concern. As long as there are no real personal injuries, everybody has to pay for their own damage. That should set the gtr guy thinking if overtaking in that short corner is a good idea and set the clio guy thinking if he's aware enough of his surrounding traffic.