I've tended to feel that just getting on the mat every day for a significant period is all you need to legitimise your practice (can't believe I'm even using the word legitimise) as well as to pass it along... and yes, call it Ashtanga Vinyasa too if you want, why the hell not. Breathe and move, breathe and move, the breath will take care of everything else of any importance, all will arise sooner or later if practiced with sincerity.
Besides if you read Krishnamacharya and then look at what's presented as based on his teaching in Mysore today there's quite a gulf already, most seem to be quite comfortable with that (enough are looking at Krishnamacharya's early writing now for it not to be lost altogether).
I've ALWAYS felt Peg and Ashtanga Dispatch are all about sharing their passion and enthusiasm for practice.
I heard about the podcast from a friend this morning who's Ashtanga practice has begun to flourish of late, practices a full week often at a shala, goes to regular workshops and intensives. She had this to say
"...listening to her podcast with Aliya, made me angry..
part of the reason i don't called myself ashtangi.. some pple think they 'own' the practice"
See too this early post from Peg