Thank you for the reminder Rudi.

I'll say 'almost absolutely dummy proof', as I saw someone put his luggage atop the spring-loaded fold-down front retention panel (which is supposed to be up), and go down escalators... in such a scenario the luggage cart does stay on the escalator, but not the luggage

Also, one must push down on the handle to unlock the rear wheels, making it awkward to pull them back from the luggage cart queue (handle swings down and forward, while cart needs to be pulled by handle).