Originally Posted by Entropy

The reason that drives people to unsportsmanlike driving is the drive to win.

Instead of attacking that bad habit. You should attack their fear of losing and they will learn to drive reasonably to avoid getting set back by a penalty.

Here's a scenario. Joe Racer has one last main to determine if he wins the race. All he needs to do is finish ahead of another racer and he'll win on points. He knows he has not received any warnings yet from the Race Director, so he decides to pull a fast one on the driver ahead of him and Joe takes the win as the other driver spins out from the fishtail manouver. The Race Director spots this and warns Joe Racer, but Joe Racer smiles quietly because this "first warning" was something he could sacrifice (without losing any points/time) to win the race.