"Photograph is not a crime" explanation. After being in the Concord Free Public Library for a while and having taken roughly 20 photos in the interior, most within view of the librarian sitting at the desk in the main room I was in for most of them, it was the photo of this bust, or more specifically the photo next to this one of the plaque describing the bust, that the librarian suddenly noticed me and made a point to run over to tell me that photography was not allowed without permission. I just smiled and said OK and asked where the water fountain was (it was a hot day out). She almost seemed confused that I didn't question her on her statement.
So much for a "free" and "public" library. In their defense, this library appears to be a weird combination of both public and private fundings where the building and the special collections (which I assume includes all the artwork and sculptures) are actually privately owned and the town dollars go to support the public circulation (books, magazine, videos, etc.) and reference stuff. All the same, it is a space freely accessible by the public.
All that said, the collection on display at this library is very impressive and anyone who happens to be in Concord Massachusetts for a visit should set aside a half hour to check it out.