everything to do with blame culture.
"where there is blame there is a claim"
we are not denying it is the farmers fault, but laws do not over rule physics.
whether the mess was legal or not, it was still there, and the OPs lad should have been riding within the limits of the conditions, which he evidently wasnt.
dont get me wrong, i hope hes ok, i wouldnt wish an accident on anyone but sh!t happens
if you go Booting around a blind corner into the front of a car on the wrong side of the road, whether the car was supposed to be there or not your still dead!
winds me up when people act as if "the law" overrules physics!
suck it up, chalk it up as a near miss and learn from it.