Buy The Books, Please

You are apparently supposed to buy the books and not just copy or photograph them. I've done this before, but certainly not at St. Marks. Sometimes you don't really need the whole book, you just want some information contained inside. Wouldn't it be a waste of paper if you bought the book for just one page? As I see it, you're saving the environment. Photograph away, just don't do it at St. Marks Bookshop.