Last week in Portugal it was a hybrid of no track limits, white line limits and curb limits which defined the track limit du jour. I'm just venting a bit, but it seems if the race director/stewards simply enforced the rules as written there would be no issue. Drivers will adapt to the limits and they can be enforced. I agree that the race director should be able to amend the rules but every week its a change (or reinforcement) related to track limits and how it is defined.27.3 Drivers must make every reasonable effort to use the track at all times and may not deliberately
leave the track without a justifiable reason.
Drivers will be judged to have left the track if no part of the car remains in contact with it and,
for the avoidance of doubt, any white lines defining the track edges are considered to be part of
the track but the kerbs are not.
Should a car leave the track the driver may re-join, however, this may only be done when it is
safe to do so and without gaining any lasting advantage. At the absolute discretion of the race
director a driver may be given the opportunity to give back the whole of any advantage he
gained by leaving the track.
There is always talk about the penalty that should be applied, in my opinion you could dictate that if you are deemed to have exceeded track limits you must establish a single lap time (which does no include a pitstop) a value X seconds slower than your slowest complete lap so far in the race (not including the first lap). X right now seems to be 1.25 sec (4 instances gives you a 5 second penalty).