‘The locking DVD case is a ubiquitous fixture in libraries and video rental
stores across the country. It uses a magic yellow tab to keep you from
opening the case. A gizmo mounted to the checkout counter can open the case
easily by sliding the DVD across its slot.
Ever wonder how it works?
The secret is two very powerful magnets. From reading the sales literature
for the locks, these magnets are supposedly only available to sooper-seekret
authorized personnel. What they don’t tell their customers is that these
magnets are also available inside every junk 3.5″ hard disk drive made in the
last 15 years. They are part of the head seeking motor.’