Michael Thomas writes:
I wonder if the right thing to do is to create a standards track RFC that makes the experimental space officially an add on to rfc 1918. If it works for you, great, if not your problem. It would at least stop all of these recurring arguments that we could salvage it for public use when the knowability of whether it could work is zero.
In 2008 there were two proposals https://datatracker.ietf.org/doc/draft-fuller-240space/ https://datatracker.ietf.org/doc/draft-wilson-class-e/ where the former was agnostic about how we would eventually be able to use 240/4, and the latter designated it as RFC 1918-style private space. Unfortunately, neither proposal was adopted as an RFC then, so we lost a lot of time in which more vendors and operators could have made more significant progress on its usability.