The recent European cookie law was close to that and got laughed at by tech people. Poor Europeans are constantly being asked for permission "Can we store a cookie on your computer?" whenever they visit a major website.
Also, how do you stop people tracking you by IP? Every web server's log does this by default. How do you allow sessions even? It's not easy to define tracking so it's different from essential operation.
> Poor Europeans are constantly being asked for permission "Can we store a cookie on your computer?" whenever they visit a major website.
As a non-European who visits the BBC, my impression is that it's even less useful than that (you can get that kind of annoying prompt just by setting cookie permissions on your browser to 'always ask'!). Instead of a prompt, you get an intrusive notice that they are setting cookies, and that your remedy if you don't want them to do it is to go away.
Also, how do you stop people tracking you by IP? Every web server's log does this by default. How do you allow sessions even? It's not easy to define tracking so it's different from essential operation.