Straight line courses wrote:
Well then, course with curves where corners can be cut should not be record eligible.
All courses are measured along the shortest possible line, curves or not. So if you "cut" curves (while staying on the road), you run at least 26.2 miles. If you don't, you run more.
So, if anything, curved courses are disadvantageous because you can run more distance than on a straight one if you don't pay attention.