Pylon Racing Code of Conduct
Mid airs and ground collisions are usually chalked up to "that's racing". Unless there is a very unusual case where intent to harm could be proven, it's a draw. Most racers understand and accept this.
When it comes to landing, the pilot's caller should always be watching the field for traffic and the position of other aircraft. He should coach his pilot right down to the roll out where to put the plane so as to avoid a ground collision. However, this is sometimes difficult due to judgement and just plain bad luck.
Randy