The aerodynamics of an open top box at speed

[Gone in 60]

I don't know that it's a flaw, more than it is an attempt for them to help you not lock your key inside the box.

You can, however, lock the box with the lid open, remove the key, toss the key in the box, and shut the lid, locking the key inside. So, it's not foolproof. Thankfully I haven't been fool enough to do that so far...