I agree with onereefnotenuf to a certain degree. We must take some responsibility for creating demand for these fish. I just purchased my second regal this weekend. I lost my previous regal to pump failure. I would NEVER have a regal angel ordered into the lfs. My justification for purchasing this fish goes something like this, its crappy logic and totally emotional, but here goes. The individual fish I purchased are already out of the ocean and in captivity.
I have a fairly large, well established reef tank. The majority of people how have salt water fish ( general population, not this message board) are inexperienced and have 75 gal and smaller, FO tanks. success this fish goes home to a FO/55 with bleached coral decoration and an undergravel filter, where the only thing that is fed to the tank is flake, the regal is DOA. I'm not knocking this type of set up. It is how I started and how I learned. I think everyone would agree is totally unacceptable for a regal.
By purchasing these fish, at least those individual fish have a higher likelihood of living in a proper set up than it would in a more typical salt water set up.
I would also argue that the majority of the impetus for controlling the importation of difficult species must come from the wholesale level. Most people who get into the hobby are out of it with in a year. People are always going to want to buy pretty fish. Most people don't know any better. They SHOULD, but they don't. As long as people are willing to pay one hundred dollars for a fish, somebody is always going to be willing to sell it to them (think crack dealer)
I wouldn't advocate governmental regulation because the government is a seven headed hydra . Once it sinks its teeth in it never lets go. It is slow to react to progress and difficult to move.
My diatribe.