My guess is they figured that people wouldn't need to put lock washers on because of the locknut. After people started installing them and saying they were too short to add a lock washer, SLR probably decided to go with a longer bolt to allow people to do what they wanted and just cut the excess off. Lock washers with locknuts may be a bit redundant, but it gives you piece of mind. I've been bouncing mine around pretty good. I don't even worry about them coming off.