Revers isn't allowed, and i personally dislike all those who use reverse while sharing the same track as myself, wither in a race or just during a practice.
There is nothing like having a person reversing into you as your trying to go around the track.
It is YOUR fault that your car is stuck, walk out and get it. It is harder for someone to dodge a moving car then it is to dodge a car that has been crashed at the boards.
All in all? o to the local track and see what they say about it.