Master Gardeners - what to make of them?

Over at the Garden Rant blog there's quite a discussion about the Master Gardener designation, and the rule that people so educated not use the MG as a credential commercially.  On one hand, these extension programs to provide interested amateurs with a lot of information and knowledge is a great thing, it's educational outreach, one of a university's missions, but the term Master Gardener is ridiculous really.  Locally, TPP corrected a Master Gardener, where upon she bristled, and said, "I'm a Master Gardener."  Yes, you're the plant amateur, I'm the plant professional and you got that wrong.  Of course, TPP isn't a master gardener either; he's a doctor of botany with decades of experience, who grew up with gardens, has always had a garden and now gardens as a hobby and for mental health, but it's a funny thing about botany, it applies to gardening.  TPP can't even count how many gardens he's visited around the world, and he learns things about plants at a level that most amateurs cannot comprehend.  This is not an ego trip about intelligence; it's the simple consequence of an ever increasing knowledge network where the more you know the easier it is to learn still more.  TPP didn't understand this until the accelerated learning effect started to kick in sometime during his 2nd year in graduate school; that was 40 years ago.  Think about that.  Someone who has been learning botany at a rate an amateur can't imagine for more than 4 decades.  A real master gardener would be someone who has degrees in botany and horticulture and years of experience running an actual garden or arboretum.  Locally an amateur Master Gardener writes a gardening column for the newspaper and it's pretty well done.  The extra education has given her the confidence to look things up and pass them along accurately.  The MG program gave her access to a whole new world of information.  A similar program exists for Master Naturalists, and a group of them are presently collaborating with TPP because they still need the expertise and direction of a professional "naturalist", and yes, it's not a stretch to say TPP is a professional naturalist, to do useful, meaningful "citizen science".  Fortunately there are some things that dedicated and interested amateur naturalists can do that might get overlooked or ignored by professionals because of the different levels at which we operate.  So my master naturalists are going to conduct a floristic survey of natural areas to generate a vouchered database of plant diversity because 100 years from now someone will be interested to find out how well these conservation areas have done at conserving.  It would be great if someone had done this 100 years ago, great but discouraging, which is likely to be the same reaction 100 years from now, but 100 years ago the idea of conservation, of protecting diversity, was really not on their radar screens, so the collections were rather haphazard in this regard.  Even still they tell us what is missing; locally: Indian paintbrush, yellow ladyslippers, and more.  These programs are certainly worth the effort for the people involved if they can find something useful to do with this education, but at the same time, they remain amateurs. In the present day it's hard for amateurs to make a useful contribution to science (doing a floristic survey will not add to TPP's credentials in any way really) unless in collaboration; the usefulness of master gardeners is less clear to me, but a horticultural colleague says they have been very important as volunteers in the development of a horticultural center, under the direction of a professional gardener.  So TPP supports such programs so long as the participants don't make overly much about the resulting designation. And that was probably the purpose of the MG rules about use of the designation.