That's what it says on the NAR website. That is the clip that comes up to the NAR site supplied by NAR, when you post a link to that specific page.
Then if you click on the link it will take you to that page where it will be expanded.
The LAW, certainly in Australia is that you cannot sell a rocket motor to an individual without them having the appropriate certification. The LAW would require a seller to be able to validate a membership that states the individual's certification.
In Australia that LAW comes through the CAA and has enforceable penalties. Additionally there are explosive handling rules that also have penalties. ( Still classified as that in Oz )
I'll leave someone else to address the US Law. Which are different.
TRA level certification is globally recognised and should be able to be verified globally, and it is. Tripoli Insurance is valid wherever there is a prefecture.
NAR certification is recognised globally, but their insurance is only valid in US and Canada.