Although a "non-free" project might be useful - I have my doubts - the case that Gerard is talking about would not be affected by it. It is just the standard practice of museums to not want to "stick their neck out" and make a legally binding statement that the images are PD. For example, the Powerhouse Museum (in Sydney) publishes its "Tyrrell photographic collection" on Flickr under the "no known copyright restrictions" license - many of these are now copied into Commons. This is in spite of the fact that every single one of the images was taken before 1929 which makes them definately PD. http://www.flickr.com/photos/powerhouse_museum/sets/72157604376512011/
It is just the legal department requirement that they not make a legally-binding statement. It is sad, but true.

I believe these photos are in the same situation as what Gerard is talking about? Is this a reasonable comparison? These Tyrrell collection images definitely belong in commons, despite the Museum not making the legally-binding PD assurances, and therefore I believe that  on this basis other museums in similar circumstances should be welcomed with open arms.

-Liam
[[witty lama]]