special OPT_OUT cookie?

[pgeorgi]

Should we special-case the cookie value "OPT_OUT"? It would be unfortunate indeed if removing old cookies meant that users who had opted out of interest-based advertising started being targeted again. Perhaps excluding the special value OPT_OUT (and asking advertisers to standardize on it?) is justifiable.

That will only lead sites to use OPT_OUT for everything, no? What's so bad about standardizing on the DNT header instead, which can and does expose per-browser UI (instead of having to work around varying dark patterns on every. single. website's "consent" form) and would contain approximately the same information without potential for being abused (as it's not site-controllable)?