I played with a group of bluegrass and old time musicians, and a "new guy" showed up. The new guy had his wife, infant, and 8 year old daughter in tow, and he carried a mandolin case. Younger than the rest of us by probably 20 years, he played a wicked mando, and comped along on several tunes he had never heard of, like Soldier's Joy. When it came his time to suggest a tune, he seemed intimidated at first, then strummed a few chords of Shady Grove, and we all jumped in as he grinned. "Didn't think you guys would any Grateful Dead songs!" he said. Later, someone played Dark Hollow, and he remarked "another Dead song!"
Now, I know a lot of purists look down on Jerry and the Boys as pop perverters of folk music. Bluegrass and Country purists also turn their noses up. But I offer this...here was a young man who might have never encountered these two great traditional songs, had he not been introduced to them by the Grateful Dead. Maybe the New New Minglewood Blues wasn't true to Gus Cannon, but I'll bet you that Garcia knew and loved the original as he did Shady and Hollow, and he helped pass it to a new generation and I raise my glass and say "God Bless ye, ye bunch of addled old hippies. I call ye folkies, and to hell w' those what don't!"