I stress this is just me noodling around, and that I'm not talking about real world risks. But: Is it possible to read unencrypted data of the flash drive the hard way?
Obviously, if it's sensibly encrypted there's no point. But a person may think they have physically destroyed a flash drive only to have left information available.
Here's some links to DIY de-capping and microscopy of a variety of ICs:
(http://siliconexposed.blogspot.com/2011/03/microchip-pic12f6...)
(http://uvicrec.blogspot.com/)
(http://dangerousprototypes.com/2011/06/27/hacking-the-pic-18...)