I have on a couple occasions, though I have not seen anything worthwhile in the last five years.
In my opinion, after I whoop your butt on the show table with the chin, it's offspring, and it's offspring's offspring, I've then got a 3-5 (in the chin below's case, 8) year history on the animal, and every generation it produces.
We'll use Studly for example, she's got a great story. Studly was the local area stud for the Lewiston pet shop. People brought their chins in and he impregnated them - they told me they'd had him for three years and he was a great breeder. I met him while he was tinkling on my leg at the cash register. Err yea. So I go back a few days later and there's a sign "bites" and make them a lowball offer of $60 for their exceptional breeding male that is tinkling on my kneecap and upper thigh from the floor.
The good news was I know for a fact they never got any babies out of "him"
You get a good eye by exercising it. By challenging yourself to be better. By taking nothing and in a generation making it something. I've only had one case of malocclusion in my herd and it was from a chin I shipped in from a "big" breeder back east. That's not to say I'll never get it, just haven't gotten it from lines with no history.
At some point there will be no "big breeders" - they'll be overseas or here on this forum. They're an aging lot and we're losing one or two every year. I just hope enough people get into chins to keep it going.
Edited to add that this is really a pointless thread, all it does is create witch hunts. You know **** well nobody is going to openly admit to it... except me, and I think we've already established that.