There's only like 6 states that still require it in beef cattle. Unless you live in the north west, it's not something many vets even want to mess with anymore. Their prices are starting to reflect their thoughts on it as well. 

Now that most of the old guys have died off and sold out you'd have a hard time finding anyone around me who has ever had a usda tag put in and most wouldn't even know what bangs is. There's really no reason for most of them to even be tagging calves at all.