Grown nephews in this case so no need to police their availability. But for those that could use that idea to protect from unauthorized use, I'm sure it would work.
Zeke, what are the dimensions on your storage building? Also, the door size? Any pictures of the exterior you can post?
Trebor's arrangement is equally impressive. First thought when I saw the ATV's under the racks is if there becomes a discipline issue, you can put them up one level on the rack and it makes access using the FEL and pallet forks mandatory......and a dad involved project..........