Tons of sites out there that turn a blind eye to such ads and that's bad. Yes, there will be some unfortunate pain for sites that responsibly attempt to block these ads as they come up. Assuming the blog post is correct and Google has implemented this correctly, it should be minimal for those sorts of folks since they claim the penalty will only occur if users are consistently getting social engineering ads. (I suspect Google will ratchet up the rate over time though, assuming these ads become less common as a result of this and similar efforts).
EDIT: See below. I'm convinced and with y'all now. Google--this is a step in the right direction and I support this action, but you do need to get your own house in order too!