I am pretty sure that the black YFZ you are refering to would have won either way, I watched them all day and never saw them doing that. You also have to think, without a tree, they do not know when you will launch so if they think you are going to hit it they want to also. For someone to be unfairly starting would be to roll in and never come to a stop.
I don't think the competition was against manufacturers, but more to show what some 450 based quad (from all makes) could do against a 727 and the 450's came out fighting.