The British Museum must be the most open print room in the world. Anyone with ID can just turn up and request anything, except for just a single restricted item (the Jacopo Bellini album). I've recently spent three days there looking at Raphael drawings, but this was the first time that I saw more 'casual' visitors. I was really impressed by the helpfulness of the staff, but I couldn't help be amused by some of what I overheard. One visitor seemed to have wandered in by accident, and didn't have any idea what she wanted to see. She was offered some 'greatest hits' ... maybe you'd like to see some Michelangelo? She demurred! Without batting an eyelid, the assistant offered some Pre-Raphaelites. That turned out to be just the ticket.
Although I'm grateful for unimpeded access, I confess to a frisson of fear when I see piles of Leonardo and Michelangelo freely handed out to any neophyte.