I'm honestly surprised they didn't learn their lesson with the whole Buzz fiasco. Didn't they get sued over basically forced social connections?
http://searchenginewatch.com/article/2050437/Google-to-Pay-8...
This time, they are putting sleazy pop-ups in ways where you'll accidentally click on the thing that connects the accounts. They might get away with it, because technically you're giving them consent when you click "OK".