I didn't know there had never been GPL lawsuit. This is going to be an interesting case...
The SFLC (Software Freedom Law Center) announced on Sept. 20 that it had just filed the first ever U.S. copyright infringement lawsuit based on a violation of the GNU General Public License (GPL) on behalf of its clients:
The Software Freedom Law Center (SFLC) today announced that it has filed the first ever U.S. copyright infringement lawsuit based on a violation of the GNU General Public License (GPL) on behalf of its clients, two principal developers of BusyBox, against Monsoon Multimedia, Inc. BusyBox is a lightweight set of standard Unix utilities commonly used in embedded systems and is open source software licensed under GPL version 2.
One of the conditions of the GPL is that re-distributors of BusyBox are required to ensure that each downstream recipient is provided access to the source code of the program. On the company's own Web site, Monsoon Multimedia has publicly acknowledged that its products and firmware contain BusyBox. However, it has not provided any recipients with access to the underlying source code, as is required by the GPL.
More information available at Linux-watch blog : First U.S. GPL lawsuit filed