I say yes, it's at least fair to ask.
Per the link, Vermont, like many states, does not require political registration to vote. So that's how Sanders claims to be an Independent, even though he's repeatedly also run in Democratic primaries, just to scare off independent Democratic challengers, pun very intended.
That pun is very intended. Per the link, yes, Sanders has a cordial, or more than cordial, link with the state's Democratic party.
Per previous blogging by me, in exchange for such cordiality, the Vermont Democratic Party has regularly quashed would-be challengers to Sanders. That would include him running in Democratic primaries as needed, as explicitly noted by Vermont's alt-weekly. (The paper is a good, straightforward, and skeptical when needed eye on Sanders, for people interested in him, but like me, always bringing a skeptical eye to politics. Bookmark its Bernie Beat.)
So, it is a façade. Next question is, how big, and how hypocritical?
My answer? At least moderately big, if not more, and mildly to moderately hypocritical. Sanders is to the left of most national Democrats, but by no means all. California Sen. Barbara Boxer, I would put to the left of Sanders, for example. She's not been as outspoken on Wall Street as him, but, she's not a semi-gun nut nor a semi-war hawk.
As for 2016 and my plans? If Sanders is still in the race by the time the Democratic primaries get here to Tejas, I'll certainly vote for him. But, should he somehow get the nomination, which I doubt, I'll still vote for Dr. Jill Stein of the Green Party, if she's nominated again, or any other reasonable Green Party nominee.
Friend PDiddie posted on Twitter that Hillary Clinton has already sewed up, or nearly so, some 500 Democratic superdelegates. Sanders is no babe in the woods; he knew this was likely before he ran. (It's also why Joe Biden made his candidatus interruptus permanent.)
But, that's also why I say he semi-castrated himself when he said he wouldn't run as an independent (I presume that includes rejecting a Green Party run) if not nominated as a Democrat. It didn't surprise me much then and it surprises me even less now. The announcement doesn't surprise me at all; the lack of thinking about political leverage surprises me somewhat, but also makes me wonder just how much of a strategic political thinker Sanders is, or is not.
As for the labels? Per Vermont law, and per the reasoning and claims of Sanders' staff, he could slap all sorts of labels on himself besides "Independent." He could be the "Brooklynite" senator from Vermont, or the "Mormonism" senator from Vermont or whatever.
Of course, "Independent" plays to stereotypical rock-ribbed New England values. Right, Howard Dean?