In another form, the answer to John is that there are no protocol police, so what consenting adults do inside their own networks simply isn't an issue that an Internet-wide spec can or should address.
That is not quite true, the inability to gain an IANA allocated codepoint can make long term private deployments very difficult, either for the protocol squatting on a codepoint because they could not get one allocated, or to the deployment of a new protocol
legitimately allocated a conflicting codepoint. - Stewart