dann mann wrote: All 4 casters swivel here in California. (clip)
^^^^^^^^^^^^^
What part of California, Dann? I rarely see a 4-wheel swivelling cart in
the SF Bay Area, where I live, and when I do, it is usually in a small
neighborhood store with generally dingy decor.

The ultimate solution to this BIG PROBLEM would be to make all four casters
swivel, and permit the customer to selectively lock out the front pair or
the back pair or no pair.

Has anyone noticed that if the wheels at the back of the cart do not swivel,
and the cart is heavily loaded, it is easier to steer if you push it
backward? It has to do with the inertia of the load, and the leverage.