I'm a PSI-PCI Cylinder Inspector.
...
Another local shop in question initially refused to fill my cylinders. I stopped by because I was in the area and needed something they sold. He went on a whole tangent about how he has no idea if I bought these stickers online, etc, etc. and I might not have the proper tools or knowledge to do the inspection. Not supporting local dive shops, etc.
I, too, am a PSI-PCI inspector. Because I let my certification lapse number of years ago, I had to sit through the entire training program a second time. I was on time with my renewal last time, so I only had to go through the online program and exam to be recertified. I can attest to the common observation that about 40% of the time spent in PSI-PCI training involves repeated and repeated and repeated stories attesting to the fact that PSI-PCI is the absolute greatest tank inspection program in the world, with the entire scuba industry bowing in recognition of its superiority. That time (and the other 40% of the time spent looking at pictures of exploded tanks) still leaves enough time to learn how to inspect tanks.
A couple of years ago I took my newly inspected tanks into a dive shop in Florida for fills. The man doing the filling looked at the sticker and asked me who had inspected the tanks. I said the inspector number on the tank was mine. He had never heard of PSI-PCI, and he ws not sure he could accept it. If it had been done by a shop, any shop, he would be sure, but.... Well, he finally agreed to fill the tanks.
The local dive shop for which I last worked had its own inspection stickers, and he would have happily accepted those. That dive shop did not have a single person on staff who had ever had any formal training in tank inspection. They did not own any of the tools required for tank inspection. But they had the local shop stickers, and that was all he needed to see.
One of the most famous tank explosions happened with an oxygen decompression bottle. The owner, who nearly died in the blast, had taken the tank to a local shop for oxygen cleaning and inspection. The analysis of the remains of the tank showed the shop had used silicone to lubricate the threads, which is a clear no-no for oxygen service. The investigation showed that the man who did the oxygen cleaning and tank inspection had never had any training whatsoever in either skill.
But he had a local sticker he could slap on that tank when he was done, and that is all that really matters.