On Sun, Feb 12, 2006 at 01:47:44PM +0100, Alfred M. Szmidt wrote:
In theory, anyone can go and make Linux a non-free program, since it is simply impossible to enforce the license there.
I suggest you read http://gpl-violations.org/ in order to see where the GPL has been discussed, and upheld, in court, following companies attempting to make the Linux kernel proprietary. Harald Welte, who started the site and wrote some of the Netfilter code, took (and continues to take) many companies to court over the use of his code, which is included in the kernel. The violations being sued for now are on a wider scale than just Netfilter, as I understand it.
Therefore I suggest that it is not impossible to enforce the GPL with regard to the Linux kernel. It's already been done, many times.
Gareth