Is "Tweet to Unlock a Free Download" a dark pattern?

The Bricks seemed like an interesting free UI design resource, so I proceeded to attempt download and then I hit a "Tweet to Unlock" wall. This irked me... the resource is not free if there is forced publicity to all my followers (before I actually get to try it) and I was not told about the terms of exchange until I arrived at the download decision (it being advertised as free extensively until that point). I would have been glad to register with the site to download the resource or possibly even paid for it. Am I just turning into a grumpy old man or is this a dark pattern? Is a "less-than-paid" but "more-than-free" distribution model a good user experience? Smells like the old "bait-and-switch".

Update 2012-10-26

ValidationBoard.com has a nice pattern of the tweet to download that did not feel like a dark pattern at all... totally upfront, product was well explained and described, transaction worded respectfully. I clicked willingly.