If little johnny had to pay a fee and apply for a permit to order the fish, would his dad want to go through all that trouble just to get one type of fish, when there were plenty of small ones he could go home with that day, without the extra hassle? No way, IMO.
From working in the LFS industry for over 10 years, I can tell you the unfortunate truth is that there are far more irresponsible fish owners than responsible. I get people all the time asking for arowanas for their 55 or 75 gallon tank. I tell them the fish gets much too large, and they say " But I've got a big tank! You can't tell me my tank is small!" I even get people who come in asking for aggressive fish, because they want to watch them kill each other for the enjoyment of it. The people happily admit this, as if it's fine and normal. I won't sell anything to these people. But there are no shortage of them.
This is that good intentions thing. What I see is a wide variety of my favorites requiring a permit because of someone else's moral compass.