This is basically what happened to P3P, an earlier attempt to regulate privacy rules with a machine-readable policy. Microsoft set IE to reject cookies by defau

This is basically what happened to P3P, an earlier attempt to regulate privacy rules with a machine-readable policy. Microsoft set IE to reject cookies by default if a site didn't have 1) a P3P header that 2) met certain requirements. It wasn't very well thought out and, in practice, required a bunch of sites to create a bogus P3P header or core functionality like "logging in" was broken for many IE users.