In some areas, branding is important. I expect state laws regarding branding are similar to here, in Canada, in that you have to register a brand and you are told what location your brand will be on. If you are fortunate and no one else has your brand in a specific location, it is usually approved. There are certain letters and symbols that are not allowed in a brand because they can be hard to read, or easy to change.
We used to brand every animal on the farm, when our herd was much larger, but we have quit now that it is smaller. If I felt we were having any problems with cattle turning up missing, I would brand everything again. Approximately 20 years ago, we did lose a couple heifers out of a pasture. We searched inside and outside the pasture but could not find them. A few days later, we received a phone call from a brand inspector at a market 250 miles from here. He wanted to know if we had sold some heifers to a certain person, as they were at the auction mart to be sold that day. In that case, the system worked and we were able to get our heifers back.
Many reputation herds also brand to promote their cattle ( eg: the hairpin brand at Leachman Cattle Co) . This brand became known throughout the industry. There are many others, especially in earred cattle. I can see how some would think of a brand as being unethical in the show ring, but I don't see it as such. I expect after one or two classes ( or even less) most any judge will know who owns animals from the big outfits.