A “best practice” is to encrypt any data that’s in motion or can be placed in motion. The reason seems obvious, if the device “goes missing” there’s no risk of data being accessed inappropriately.
Portable Computers and Portable Storage Devices are examples of this type device. Whole disk or whole device encryption can provide the necessary safeguards. This can be accomplished easily and cheaply, either through commercially available solutions like PGP or free by using a program like TrueCrypt which can be found here, http://www.truecrypt.org/.
What can happen if you don’t take these precautions?
“All of East Chicago Public Library’s records on stolen drives” – Indiana State Police arrived at the East Chicago Public Library on Friday afternoon to investigate the reported theft of computer hard drives holding all the library’s records. Source nwi.com