This should be "Opt In", not "Opt Out". The problem being that everyone knows - including Google probably - that people wouldn't. Because, oddly enough, most people don't want their face in the search results!
Anyway, perhaps more interesting is that if Google+ data is now being leveraged to improve search results, it could be taken as an indicator that other products like Google Analytics could be utilized at some point. Or that it already is. And before anyone says it, I know G+ is used for author markup, but this is quite different in that it is leveraging behavioural data.
Or put another way: if they are happy to use G+ behavioural data, why wouldn't they also use Google Analytics?