"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..."
