I don’t (ahhhh, the joy of apostrophied contractions) have a strongback, but I do have some shop stuff on wheels.
The rolling shop stuff has wheel locks; a lever and “brake pad” that keeps things immovable. The table with all of the sanders has wheels locks, so I can move it around the shop and it isn’t walking away from me while I am using a sander.
The best of those wheels/locks came off defunct double-stacked, water-jacketed laboratory incubator platforms. Those stacked incubators weighed close to 1000 lbs combined; even drained of water they required a scissor jack to move. Those are some serious freaking wheel and locks, with large wheels and good bearings.
I gave a 4-set of those incubator wheels to DougD, and another 4-set to my friend Bart for his shop. Bart used them to make a rolling TV cabinet. Um, Bart, it’s a danged television, not a hemi engine block. I’m not sure if Doug has found a use for his yet. Probably for a rolling beer fridge.
I like having wheel locks on everything except the shop and office chairs. There are four of those “office” chairs in the shop (shop visitors and etc). Not just for visitors; the shop cat claimed “her” chair, and having a spare rolling chair is a handy as a catchall platform for tools & materials to wheel beside me while working down and around the length of a boat, even while standing.
(I sometimes rolled the bothered-by-nothing coon cat along beside me in her chair for company. In the realm of useful shop partners she ranked #5, just behind Joel, DougD and my sons. She drank almost none of my beer, and never got wet epoxy on the door knobs)
However, a couple of those rolling chairs have wheel locks on two of the four casters. At least once a week I inadvertently lock a wheel with the heel of my shoe, try to roll sideways or backwards, and spin around 180 degrees in a locked-wheel circle.
Wheel locks on chairs? No. On everything else, yes please.