Enchantment - it most likely coulds the mind to prevent the target from taking notice. An Illusion could make it appear mundane, but it wouldn't necessarily affect the target directly.
By the way, I have heard that there is a book out there that has the words "Please Ignore" on the cover. The cover was so effective that nobody ever shipped the book from the warehouse and not a single copy was ever sold. The marketing team who created that cover was of course sacked. The new company hired to replace them came up with the extremely effective cover, "Don't Panic," and the book of course went on the become the most wholly remarkable book in all of the known universe!