Does anybody know if amazon actively checks the books put on your kindle via their email service? There are a number of books that I own in dead-tree format (s

Does anybody know if amazon actively checks the books put on your kindle via their email service? There are a number of books that I own in dead-tree format (some of them, multiple copies in dead-tree format) that they don't offer in the kindle store. This sort of move really scares me; I have been contemplating moving some of them to the kindle (I have the books in .txt format).