Many thanks to all for your comments and thoughts. There are a number of different issues on the table that deserve further discussion and clarification beyond this conversation.
A professional certification that is developed meeting international standards for credentialing bodies provides a demonstrated means of raising the bar for practitioners. NABCEP is one example. As Richard Lawrence points out, NABCEP has meet the rigorous requirements of ISO 17024 through an exhaustive application and on-going assessment process. Less demanding credentials only confuse the market and customer choice.
The ongoing discussion on certification vs licensure continues to promote lively viewpoints. If constructed following essential requirements, both protect practitioners and the public. However, a general license, such as an electrician's, does not necessarily include the specific requirements of knowledge, skills and competencies for installing a photovoltaic system. On the other hand, an unlicensed person should not be connecting wires. State licenses also result in a multiplicity of disparate requirements which can curtail practitioner mobility and complicate the training and education process.
Thanks Ed for your shout-out about SEIA's commitment to quality training. The solar industry has taken a no-nonsense position that demonstrates quality matters.