I don't know such definition frankly. And to the best of my knowledge there are plenty of things which people call "protocols" strongly prescribing actions non-verifiable in the very sense you used. That said I'm not here for a terminological discussion. We may call it green cheese, but it's still a useful feature.
Nobody claimed it isn't a useful feature. The only claim I made is that it cannot be mandated with an open protocol, so if you expect 100% adherence in the name of privacy, you're setting yourself up for disappointment.