In summary, it's up to Wikipedia to adopt its own policies. Personally, I would avoid too doctrinaire an approach; I would more tend to assume that if one takes a fair-minded approach to including material with uncertain copyright status the worst that can happen is that some ghostly obscure heir will emerge from the woodwork to make his claims. More likely, he will thank us for reviving the memory of his dead ancestor.
Ec
With due respect toward Ray's very thoughtful analysis, I can't agree with
that conclusion.
Wikimedia Commons currently has 276 administrators and over 6 million images. Compare that against en:wiki's 1,714 administrators and 3 million articles and you'll get an idea how thinly things are spread. Commons has a serious deletion request backlog.
Experienced contributors--particularly at the featured content level--have an obligation to set the example and put the best foot forward. Yes, it can be frustrating to research copyright. It would be considerably more frustrating if a copyright owner who didn't thank us for the appropriation complained to the press.
About two years ago the featured picture program had an editor who was nominating copyright violations and running a vote stacking sockfarm. He had actually gotten a copyvio promoted to featured picture before we realized it; fortunately we caught onto the problem before it ran on the main page. Afterward a single administrator undid his siteban without discussion. Last fall he was banned again when he actually threatened another editor. During the noticeboard thread it turned out that he had gone over to the DYK program and had resumed submitting copyvios there--which apparently site culture was not doctrinaire enough about addressing.
If a fellow who had already been sitebanned for copyvio can return and continue copyvios for a year at a venue which runs on the main page, then perhaps a more doctrinaire approach is exactly what we need.
-Lise