The Master Gardener program is a volunteer program administered by each state's land grant college which also runs the Co-operative Extension Service. Each state runs the program differently,which accounts for the wide variation in the charge to enroll in the program. Also each MG unit is often unique unto itself. The local MG unit is supposed to be supervised by the local Extension Agent but if there isn't an agent the MG unit can run itself, under state guidelines of course.....or supposedly. Each agent runs the MG program differently, some are very involved, others aren't. Some MG units levy dues, others don't. The two I've been involved in do not. The dues may offset some costs incurred by the unit, my units use plant sale proceeds.
All this being said, or written, each MG program is run in a manner often unique to it's state and even it's county. So while the MG program is nationwide it's administered at the state level and overseen by the local extension agent, if there is one.
Don't know if this helps or just muddies the water,

Seems that you see it the way I see it. I just didn't know if there was a national bylaw hidden under a rock some where.
Thanks
Lynn

Cooperative Extension is such a funny animal. It is just the way nmgirl describes it above. Like 4h which they also run, sometimes you can find a program which is well run, professional, organized and a credit to their educational mission, but also and unfortunately all too often you can find programs which are sloppy, amateurish and an embarrassment, which disseminate incorrect information, old wives' tales and folk knowledge which have little or no basis in fact or science, and which are staffed by dopes who couldn't or wouldn't research a subject if they were in a room full of encyclopedias. Sometimes you will find both mindsets within the same extension office.