> The "opt-out" is just another cookie. There's nothing special about them either, they can be used to track return visitors just as well as any other cookie. I'm sure they're not, because that would be against the spirit of the law ..

How is a opt out cookie the same as tracking cookie?

Isn't there a clear difference for a cookie:

    is_opt_out: true

Compared to a cookie:

    tracking_id: 374739585483292

Sure the first one can tell server "this is a user that had visited the page in the past". But this is nothing compared to the second one which tells server "this is this specific user"