Haven't installed the extension for these two reasons.
Also, while I strongly believe that the tech industry re: surveillance, data-mining and data-sharing is completely out of control and deserving of a tool like this... I'm not ready to cross this line and become this kind of activist for change. There's a war going on and our online rights to privacy have been completely stripped away - with things getting so much worse.
As a result, I do understand others using this extension and hope that this tool (among others, especially long-needed legislation which the government opposes) changes things for the better. Whitelisting/Blacklisting could help solve the fav sites issue but it defeats the purpose of this extension when there is so much at stake.
It was my first concern too, and I still wouldn't be comfortable to run it, but it's not as though the security question was unaddressed.
(I do object to the possibility of getting your favorite sites blacklisted by ad networks for low-intent clickthroughs or botting.)