What you mean is that *you* don't do it. I've had a 622 and a 722k installed by Dish and neither installer changed it from. 480p. The installers were excellent in all (other) aspects too.
I don't just see my own work, you know. Service calls of one sort or another are a huge portion of our workload. I've only ran into a handful of cases where the resolution was set to 480p when it should have been set higher. It was either a customer who was shipped a receiver and connected it themselves, or it was done by a particular retailer in our area that we've had a lot of trouble with. Only once did I see it done by an in house tech, and it was his first week on the job. So, no this isn't standard practice. It's a fluke.