The overtaking driver should take full responsibility for any overtaking attempts. If the trailing driver manages to get side by side and has the inside line into the following corner, then the overtaking driver normally has the right to pass.
When fighting for position, a overtaking opportunity will almost always evolve. The driver in front is allowed to alter his line once. If the drivers are side by side, a line change is not advisable.
A driver being lapped should get off the racing line immediately, and allow the lapping driver to pass without incurring any time-delay, or else, a penalty might be given to the lapped driver. Getting off is best done on straights by moving away from “the racingline”, but not braking in corners which might impair the lapping cars plans to overtake.
Drivers should act as if they actually could get hurt and have payed the car themselves. Ie, be careful. Consider also that peripheral view in simracing is limited. Adapt your driving to that, ie keep distance to other cars.
In cases we have to judge whether a car was on or off track we look at if at least2 wheels were inside the track’s white line, which is considered OK. In cases where track is layed beyond the white line (eg Start-finish straight on Paul Ricard, Castellet) it is allowed to cross the line with all 4 wheels.