And what if training limits change, the old certs cannot change. A cmas DM/3* has a 60m on air cert. That is still no technical diving. But now new cmas 3* are only rated to 40m or so. On my 'brevet international' is no depth stated, but I did it under the PO2 of 1.6 limit on air, so that means my 3* is over 60m rated.
This directly states a problem you sometimes have. Agencies change rules, but certs are already given with other rules. You cannot revoke limits from older certs. The same happened with advanced nitrox, this was a 42m cert, but is now a 40m cert due to iso limits or so, I don't know exactly. But my cert is still a 42m, even if there is no limit written on it. I did it in the 42m time. (Ok, I am full trimix certified, so don't have any limits anymore, you can be trained till 100m depth, but then go deeper if you want,but if you do, do it safe please).
In my country there are no laws about diving, so everybody can say 'I am instructor' and can start an agency. They are only not in iso/nen or (w)rstc or euf. So you can get problems when you go with this cert to a divingcenter.
For technical diving, there is no iso or whatever, that means, acceptance is based on goodwill. Normally you won't have any issues if you stick with the big tech agencies.
I think a lot of divecenters limit too much, only because they are afraid of responsibility. But most times when they state this is a law, there is no law, it are only lies. I think we must accept more independent diving and solodiving. The boat is only a taxi to the divesite and the guide is optional. We learn to dive without guides in Europe. We go diving on our own most times. Solo or with friends. Boats are only taxis to a divesite. If you are a divecenter owner and you think even divers with over 1000 dives on 200 different divesites all over the world cannot dive without supervision, please be honest, do you trust your dm with only 62 dives more? Even the open water diver is already an autonomous diver. If not, was the instruction not good enough?
Because there are no laws, as instructor you can only advice people to stay within training limits. But if they don't do, you cannot do anything at all. Of course you can refuse to teach a diver, but to judge about people doing things outside a certification limit, that is not possible, and is officially talking behind backs if you do. There is no police who can give fines. Only advice is possible.
And remember, diving is the only sport where you can only learn by doing courses, there is no autodidactical way accepted. But would learning to dive safe be possible the autodidactical way for some people (with some friends for example)?