It shows that CZ has been wise to show caution over these issues, but it also suggests that we should resist attribution claims being made which are not legally valid.
LOL.

Believe me a thousand time over that heirs of original authors, and museums and the like who make PD materials available to CZ, are not going to sue CZ for following the widely accepted and requested convention of crediting them, e.g., John Doe / Acme Museum.
What it will do, in fact, is give CZ a
good reputation, with the credibly hopeful end of allowing us to host images we'd otherwise not be able to without charge.
