This is not going to be effective unless Red Hat really pushes for damages. Shutting down Twin Peaks products is not a big deal, they will just release the source of their mount.mfs and/or rewrite the mount, and then push out a new version that doesn't violate mount's license.
Except that GPLv2 doesn't work like that. Once the license is violated you permanently lose the rights granted by the license. So even if Twin Peaks fixes their stuff and comes back into compliance, they do not get their rights back automatically -- the copyright holders have to explicitly give them back these rights.
This is one of the important differences between GPLv2 and GPLv3.
