Cycling in Melbourne Australia
I did. Have done.
Useful for maintenance of bikes too, if you don't have a bike stand. (Or, your bike is a cargobike and you want to suspend just the rear, coz you'd need a forklift to lift the thing) ;)
They're 20kg rated. That'd hang a Greenspeed trike. (Well, if a Greenspeed trike weren't such an awkward bastard of a thing to hang balanced. ;-)
My 1993 Giant Iguana (chromoly) only weighs 18kg with front and rear racks, empty panniers and full lighting rig. :-)