At my local Home Depot the router bits are displayed on peg hooks with these little red plastic anti-theft dinguses securing them. I guess it's called a "peg hook lock".

Inside this device there is a spring-loaded (I think) plunger that locks it in the closed position, preventing the device and anything behind it from being removed from the hook. The "key" is really just a magnet, which when applied to the bottom of the plastic housing, pulls on that hidden internal plunger to unlock the device.

One evening, after searching to no avail for an employee to help, I went to the furniture hardware aisle where they sell small magnets that you could use for drawers and the like. Borrowed one, still in its plastic clamshell packaging, and used it to remove the peg hook lock and retrieve the router bit I wanted. Then I returned the peg hook lock to its locked position, returned the magnet to its aisle, and purchased the bit feeling rather proud of myself for solving this puzzle game.