No, I'm not so sure about the protection as captain part either, which is why I was questioning Netserk's suggestion in the first place.
But then, on the rest of your post, if it's likely that Sky as a whole were given some carte-blance protection in 2011, then you still come back to the original question that Netserk was answering - if the whole team had protection then why was it primarily Froome (and perhaps to a lesser degree Porte) that took advantage, and why haven't the other more promising riders on their books at the time (EBH? Geraint Thomas? Peter Kennaugh? Lovkist? Even Ben Swift has a more promising junior Palmares than Froome) been able to get anywhere near taking advantage of this protection?
Which to me points towards Froome beating the passport off his own back (either through clever doping, or riding clean).