Absolutely. Earth magnets (neodymium magnets) are safe to use and won’t damage cameras, SD or CF memory cards, laptops, smartphones or tablets. In fact, most electronic devices contain stronger magnets than in the flap cover to perform different functions, for instance hard-drives contain a magnet to spin the head. So why the concerns? Because older technologies based on magnetic fields were susceptible to magnets (floppy disks, VHS…).