Many years ago - my own clubs 1st XV has relegated from the 1st division thrice since then - I was watching us play away against the oldest club here in the Netherlands. Their coach had relatively recently (way back then) coached the Dutch national side, and both of us were spectators.
My side was losing - it was probably the third last time they got relegated that season - but not uncompetitive. Our full-back ran 20 yards or more to try to collect a huge kick from their 22 (it was already called 22 metres rather than 25 yards) and failed to get his hands to the ball. Nor his chest. The aforementioned coach and I happened to be in an almost perfect position to see all this. The referee - 40 yards back up the field near where the kicker had been - whistled for knock-on.
My comment to the opposition coach was that 'we' were unfortunate to get called for a knock-on when the ball had not touched the hands or arms, or indeed the upper body. Here is the kicker: the coach was convinced it was a knock-on as long as the ball travelled forwards.