I have forgotten the recent example, but there are sites that don't have a banner at all because they don't track users and others that see the Do-Not-Track header and replace the banner with a discreet acknowledgement.
Good point, a reasonable response to the who debacle would be to get the legislature to mandate that a HTTP headset similar to do-not-track must be configurable on a browser basis and all requests that hold it must be seamlessly executed as if the user had pressed the “do not agree” button previously.