I corrected a fat guy today doing horrible squats, knees over his feet, probably not even half way to parallel with the deck. I was nice about it, like; "excuse me, I know you're doing a lot of weight (he was only doing like 3 shitty reps), but you're knees are really going over your feet." All he said was he was doing low reps, high weight so it didn't matter
then he proceeded to tell me about how he just started a bulk cycle 2 days ago. I said I was jealous because eating a shit load of carbs is awesome; he replied with "oh no. I'm doing a clean bulk. like 400 g of protein and only a little bit of carbs and fat." I literally said "oh, ok." and walked away; looked like a fucking jackass, I didn't are.
oh his high weight wasn't even 3 plates. Only 275
EDIT: and not getting full ROM for reps is silly. If it was once or twice then you stopped because you didn't get ROM, that would be different.