Funny thing is that at one time, photo editors were looking for those markings on the slides they received. Slides that had the V marks on them were instantly said to be better pictures than those without them!
Also, the notches were the source of the big Bronica scandal years ago. In a bronica add, they were bragging about the quality of their optics and cameras yet the image they were showing contained the tell-tale signs of being shot with a hassy!