E-Dawgie, I would think that the design was to make it easier for assembly at the factory. Maybe the lines could be started and tightened quicker while the frame was traveling down the rail. Just a guess tho !!! I took mine out and used a different (tab) on my front when I re-plumbed it for disc brakes. They do look a bit strange if left there when you clean up the chassis. I like bulkheads anyway..
Jon