I guess I am just too old school! In general, I am not in favor of any form of improving an animals appearance other than using clippers on them. While, I think it would be possible to band a navel successfully, and am pretty certain there are also cases where it has been done improperly and it has caused infection, pain or even death. If you are going to band the navel, why don't you surgically lower the steers flank while you are at it?
These practices are not new in this business. I can remember over 40 years ago, of seeing a good looking set of bulls at a bull sale, and something just did not appear to be quite right with a couple of the bulls. When no one was around, I ran my hands over the bulls and when I felt the inside of the flank area, I could still feel the scar and stitch marks from this guys attempt at making his bulls look better. I have never bought an animal from him, even though this outfit has produced some pretty good animals over the years.