"Software licensed under the GPL open source license is
considered to be Free Software but that doesn't mean it's free as
in beer and that developers don't have rights. As four cases in
point in 2007, the Software Freedom Law Center (SFLC) has filed
legal suits against four different defendants for alleged copyright
infringement of the BusyBox's GPL licensed code.
"BusyBox is a collection of UNIX utilities that have been
optimized for size and are most commonly used in embedded
environments. BusyBox is licensed under the GPL which is a
reciprocal license and requires that users make the source code
available to end users..."