Good article. As an aside, 'grades eight through ten' only makes sense if you're an American. I can only guess how old they might be by assuming that grades count years and thus these are probably teenagers.
Teaching the principles rather than just 'look it's free' is definitely the right way to go -- after all, if you don't care about copyright law (like essentially everyone not actually employed by a corporation that makes money from its current form) *everything* is free of charge these days.
I would think that introducing people to programming if you don't yourself have the fire is a bit of a lost cause. The really dedicated ones will have been hooked for years already! (But, yes, it would be nice to, ahem, hook a few more. This sounds disturbingly like propagandizing or drug pushing, only programming is *good* for you. Honest! Look what it's made of me, er oops)