Anbody ever question why you'd put a drip rail under the top?

[skorpioskorpio]

When you look at the Blazers and Jimmys, knowing it's basically a hacked shortbed I guess you just never question it, but if you think about it, and look at other vehicles that have removable or retractable tops, you have to ask, why is there a drip rail above the windshield and not on the front lip of the top? Seems like this would only promote leakage and eventual failure of the gasket. Why is it there?