No, special flowers want to be treated special, they don't want to prove a level of competence, they just want to say they are competent and have everyone believe it. Kind of like Dr. Deep. I might have questioned him, but others took him at his word. Of course, solo diving isn't on the same scale as 1,000 foot O/C dives.
Certified solo divers, OTOH, have been through some course of instruction, much like cave divers, advanced wreck pen divers, and others. They have demonstrated their competence to someone somewhere who agreed that they had some minimum skill set to solo dive. My wife's cave instructor was very clear that she had the skills to dive solo at the end of her instruction. This was years before any type of solo certification came out.
Look, I believe and agree that solo diving is a mind set as well as a skill set, and to me the weight is more heavily on the mind set side. I know a number of self taught OW divers who still dive, they still don't have a cert card, and I still wouldn't let on my boat. My uncle is one of them. I know a bunch of OW divers who regularly trimix dive, who deep air dive to far more than 200 feet, and "Wash up" with a hang bottle of O2 from their transom, they don't carry it with them. Looking at any number of profiles from the Hell Divers would make most certified divers cringe. And, they have a far higher accident rate than recreational diving as a general rule. They don't go on charters, as they own their own boats, compressors, and blending systems. Their statements are typically something like "why should the rules apply to me? I've been doing this for years." Good on ya. Keep on doing it. Just don't do it someplace where someone with deep pockets (namely my insurance company) will have to face the deceased's heirs and explain why industry accepted standards weren't followed. My insurance agent, the one who insures most of the boats on the East Coast, will not do business with many west coast boats for in-water liability for this exact reason.
But then, we're on the East Coast. We don't have that stubborn independent streak that many on the west coast have.
Sorry, all, for being hooked and drawn back in.