The original poster should have been at an event I attended last weekend. Of the fifty odd aircraft departing only two went to the furthest extent of the runway to start their take off run. Does this suggest that the other 48 were being negligent or careless? Or could it be that they (correctly) calculated that the amount of runway before them was sufficient for a safe departure.
The was no apparent significant difference between the two that used the earlier start point than many of the others.
D.