Bakers were under constant suspicion of cheating customers and the regulations. Adulterated flour was a big concern too, not just loafs too small or airy. To manage their reputations, I think bakers would rationally take any edge they can get.
I totally agree that bakers would give an extra loaf to help their reputation. I seriously doubt this was done as a way to stay in line with the law as the linked article claims.
