More generally, to
bootleg is to transport
contraband of any sort. While the term originated during
Alcohol Prohibition in reference to the carrying of contraband
alcohol in one's boot, it has survived long enough that distributors of
FDA-unapproved
AIDS medicines have been described as
bootleggers. (So, for that matter, has
Han Solo.)
Bootlegging is also the second-most-common term for the act of distributing proprietary software in violation of copyright law. The most common term is, of course, piracy -- a term whose usage has the unfortunate connotation that one believes copyright violation to be morally equivalent to rapine, robbery and murder on the high seas.
The image of the bootlegger, like that of the seagoing pirate, is a somewhat romantic image and may seem ill-applied to unwashed warez d00dz. Nevertheless, copyright violation is a crime of contraband, not a violent crime like piracy at sea.