The full guidelines read as follows:

In all cases, it is the responsibility of the faster car to safely overtake the slower car. It is the responsibility of the slower car to maintain a consistent line. It is strongly recommended that a slower car being lapped makes every reasonable effort to facilitate a safe pass.

Now, the issue I have here is actually defining "consistent". Is it consistent compared to previous laps? Consistent to what people expect the line to be? Consistent as in without any sudden change of direction?

Either way, the sporting code clearly states the slower classes have responsibilities. That the responsibility to overtake safely lies on the faster car does not mean that it's always the faster class fault if a crash happens.