A user sets generic preferences, upon which her agent (browser) automatically acts.
She can now browse the Web seamlessly.
First, she browses a web site with a privacy practice complying with her preferences.
Nothing visible happens
Then she encounters a site with "exceptional" practices outside her generic
preferences.
Perhaps a sports news site wants to collect her favorite teams for a customized news
page.
The user is prompted if she wishes to consider other alternatives, consent to the
exceptional practice, or to go elsewhere.