Just to play Devil's Advocate for a moment...
With regards to a competency test, it sounds great on paper and in theory. The practice of it would be insane, as it would invariably cost money for the testing process - money that could be spent towards proper husbandry (caging, heating/humidity control, proper diet for the herp in question, etc.). Also, where are the "correct" answers coming from? What might be good care for one person in one part of the country may be different in another area with different climate and humidity. Granted there are norms, but the key to good husbandry is how to obtain these optimal conditions, not just spouting off facts and figures.
The compromise there would be to require a permit akin to Florida's ROC system, but instead of just getting a permit with that $100 annual fee, you'd be certified/approved to keep the species in question.
As far as musical snakes go, for some people this is the only way in which they can gain the experience to keep rarer and more expensive animals. Denying a person the experience of keeping a more advanced species purely based on their (or their parent's) economic or social situation is potentially robbing the herpetological community of the next Bob Clark or Allen Repashy. Plenty of old school herp enthusiasts "made their bones" (myself included) as kids catching & swapping turtles for frogs and salamanders for snakes. In this respect, it's building a stronger, more educated, more experienced, and an even closer-knit community by giving more people the know-how to properly care for these creatures. As for the trading of critters as one would trade baseball cards...well, don't parents of human children send their kids to camp or a relative's every once in while? Is this a shock to the system of the child? Hardly! Animals adapt to their situation, or else they die, making room for a stronger species. That's natural selection, which has been doing a bang-up job on this planet for the past 3,000,000,000 years.
Just some food for thought.