Hi, I am in the Pittsburgh Area. I do between 10-20 boxes per week but I do not mark my halves.
Although at a local bank a man orders halves, checks them and returns them immediately, still in box and wrapper - it took a teller I went to high school with to tell me. Every since, I decided I didn't want his leftovers, I have been doing a lot better. But from my years of doing this - I can tell people have claimed certain areas. I even had a teller tell me "Oh we don't get those in this bank." When I asked if she could order me some she said "We order six boxes per week but some man comes in to get them." Some banks cooperate, other's don't.