Thanks, it aroused my curiosity a lot because neither me nor anyone else we know have had any leaks at all. Many trucks with Air-Lift bags etc, Over many years of use, and well over a million total miles of travel use combined. Not saying that nobody else has never had a leak as I'm sure it has happened. However, what you have experienced in having so many leaks occurring is simply off the chart times 2.
Of course, you could simply run a single air plumbing line fill to each side of the rear bumper and clip or screw the fills there and still have fully adjustable lift each side capability and you wouldn't even spend $10 doing it. I'd drilled a hole under the bottom side outside ends of the rear bumper and mounted the fills there pointing down so water and dirt isn't a factor and besides, each has a valve stem cap on it. Totally un-noticeable. Can always get to the fills anytime if necessary. Only 2 clamped hose joints to each bag that could ever leak and done right, they won't and never will! So simple to do and ultra cheap and lasts longer than you'll probably ever own the truck. Problem solved!