Ford has specifically stated
Ford has specifically stated that simply using the Linelock system would not void your warranty. Participation in a sanctioned race of any kind will void your warranty if they find out, but when they made the comment about how linelock was only for racing purposes and racing voids your warranty, I spoke with a Ford rep who clarified that just using your linelock - say to do a big smoky burnout in your driveway - will not void your warranty. Not being allowed to race is true of all Mustangs and plenty of people still do it...and dont get caught.