You make a valid point about yield monitors.  Their accuracy is entirely dependant on calibration and good operator practice.  I would only trust yield monitor data which I have harvested myself, or which was done by someone who I have complete confidence in to possess the appropriate attention to detail and knowledge of both technique and theory of yield monitor operation that is necessary to do a good job. 

It all comes down to reliability.  Replicated, randomized university plots are defensible scientifically and statistically.  Nearly everything else you can find to look at is not.  If you want to depend on unreliable information more power to you, but I've seen too much questionable "data" out there to be willing to believe much of anything which is not either first hand, done by me (and I've done lots of trials which did NOT produce usable data) or else done according to defendable scientific  proceedures.