Parents please explain to your drivers that the back markers are new to karting and they are learning and they are NOT there to hit and bully! We could have had a serious injury in the first heat when a back marker was put in to the tyre wall on the back straight.
It is also NEVER appropriate for a parent to speak to someone else child in a aggressive or abusive manner. I you have an issue to to the Clerk of the Course and he will speak to the driver if he agrees with your take on the situation.