In my experience, when Will Fly says some piece of technique is a good idea, it's a good idea. This can be true even if it runs counter to my own practice.

But…

That planted pinky thing means when your pinky is forcefully braced on the top restricting the movement of your hand. It doesn't mean your pinky mustn't touch the top at all. Many notable guitarists allow their pinky to touch and glide, ever so lightly, on the top as a depth gauge for flatpicking. As Will notes, it must never be allowed to restrict the hand.

Merle Travis famously planted three fingers squarely on the pick guard of his guitar, much the way a left handed pool player might form his "bridge." But Merle played mostly with his thumb and index finger and most of his work was on electric guitars that a) weren't sensitive to acoustic damping and b) the pick guard wasn't attached to the top of his (electric) guitars. If you watch the film clips of Merle with his Bigsby-Martin, he's less rigid with his right hand placement.

      - Mark