IF they can sell something, then they could care less about whether it meets "code" or not, and many items do not. Rough plumbers are exactly that. They usually have ZERO knowledge of what happens once they leave the job. In fact, many of them do not even know why they have to install cleanouts, or where they should be to make servicing the system easier. Which could be a problem at a house where I was yesterday, unless the plumber did install a cleanout, but did not make sure the sheetrockers would not cover it up.