[baD]

My views are:
There is no simple instruction to cover all possible incidents.

There are racing incidents, carless driving and complete take-outs for a start.

Main point - Marshalls should never interfere with other drivers (don't take that the wrong way)
or put themselves in danger.
It is always a split second decision - funny tho sometimes drivers with the quickest reaction times for driving can have poor reaction times for marshalling.

It is not always a case of marshalling cars in the order they crash, unless there are separate unconnected incidents.
If A is at fault colliding with B, then A should get away first. Not an easy decision always. If A collides with B and in so doing they take out C coming along behind, then the order to get away should be B, C, A. i.e If A causes a pile up, A should be last away.
If a marshal does cause an accident, before getting to the crash he was going for, then the cars he collided with get put back in their running order, if possible, before the original crashed car, he shouldn't have crashed.

Any marshal who doesn't put a car back facing the right way should lose his TQ.
Failing to spot an incident by 'daydreaming' should incur a time penalty on their best Q of the day, or on their Final time, or even their next meeting if penalising their Final is of no consequence.