You are right, of course, but it may even go beyond that.It's a racket in the US, but with a different set of players. Since it isn't actually regulated here, the tank inspection can be done by a tank monkey without certification by anyone but the senior tank monkey. That shop sticker is just as valid as a PCI stickèr, and without certification as a inspector the profit margin is higher.
A couple of years ago, in preparation for my annual stay in South Florida, I cleaned and inspected my tanks, putting on my official PSI-PCI stickers with my official PSI-PCI inspector number on them. On my first day in town, I took them to a shop I had not used for fills before, Force-E in Pompano Beach. (I mention that because it is a long-established--1976--and highly reputable operation.) The man doing the filling looked at the stickers and was absolutely baffled. "Who did this inspection?" he asked, clearly suspicious. When I said that I had done the inspection myself, he was doubly suspicious. I soon realized that his question meant "What dive shop did the inspection?" I guess what he usually saw was stickers with the name of a dive shop on them. He had never heard of PSI-PCI, so that name had no meaning to him. He eventually agreed to fill the tank.
If my stickers had the name "Joe Blow's Dive Shop" on them and had been inspected by a new employee who had no training whatsoever, he would have filled the tanks without any question, but he was quite concerned about a tank certified by some random guy trained by some unknown agency.