Dude, you're like 6' 10"! Reach up and put 'em on the roof!

Depending on how much you want to spend..., I'd go with a hitch-mounted one that swings out so the gate can be opened while the bikes are still on the rack. And it's easily removeable when not in use.

But if you're worried about them being swiped (or parts of them), put them inside...assuming you're not hauling little one(s) around though.

Tough call...you know me and my racks though.