Might be a regional thing too, they do it at both the marts in this region. I've seen balls drop the price of a lamb by ten pounds (one of mine) and I know he was the same size and just as good. If I wanted him left with the others I could say so but they know how to get themselves the most commission so I left them to it.
It would be a brave farmer who passed on a dud tup up here, the farmers tend to know of each other even if they live 30 miles apart. Maybe because there are so few marts and not much else for them to do but that seems to be where they go for a day out, lol.
We have a neighbour who has swicked a few people in the past and is now known right across the NE. When asked where we live we're always asked if we know him

Reputation is so important.
I forget sometimes how different it is here, when we first moved up in '94 I thought it was like stepping back into the past forty years, no crime, safe to let kids roam, no door locking. Once the police went round a car park in Banff checking car doors and hardly found one locked! The headlines in the local rag the week we moved here were about a man who had fallen off his bike into a ditch because a car passed him too closely, front page news! it tickled me

I hear about sheep rustling and farm theft further south and feel so sorry for them.