It is if they don't redist the kernel code they're using - if it's GPL'd, and you redistribute the binaries, you acquire the responsibility to redist the source.
106 karma · joined May 24, 2013
EDIT: Apparently all previous history was lost when they implemented CVS, circa 1997. We could always ask someone in the oldest maintainers file available (https://gcc.gnu.org/viewcvs/gcc/trunk/MAINTAINERS?revision=1...) and have the real answer.