The idea is appealing: an LED flashlight with a strong magnet in the handle.  You give the flashlight a few good shakes.  The magnet slides back and forth through a coil of wire which, we all know from high school science class, creates an electric current.  The current recharges a capacitor, and voila! a light that never needs batteries.  Great hurricane survival item, right?

Well, except that most of the ones I've seen are fakes made in China and sold by the boatload here for a buck or two or five.  How do I know they're fake?  I've taken some apart.  The "magnet" is not magnetic.  It's just a hunk of dense pot metal.  If you follow the coil wires, the ends are loose; they're not even connected to anything!  These flashlights depend on the stored power in two disk batteries, and when that's gone, the light stops working forever.  Of course by then, you won't remember where you bought it, and for a few bucks you probably won't care enough to pursue a refund.

All the fake lights I've seen have common features: a translucent plastic body with rows of bumps molded in, a black screw-on top around the lens, a black switch and of course the very noticeable "magnet" and bright copper coil.

There probably are some real working shake flashlights.  But these are not the ones you're looking for.  The rip-off artists have unfortunately given them a bad rep.  Nothing to see here.  Move along.