Oh the hyperbole - a lawsuit over faulty shopping carts does not mean every parking lot needs to be smoothed, every sport ended, and every renaissance fair made safe for hunchbacks.
When you pick up a shopping cart at any one store, you expect it will work like all the other shopping carts out there - I'm sure this woman would've reasonably believed it was just like the ones she used at the grocery store. Notice the contrast to walking through an unknown parking lot or rocky field - you expect those things to present some difficulties.
This particular cart wasn't up to speed; it was apparently junk. And its faults were things that you could reasonably foresee would cause injury to at least some of the customers at the store.
Is it more reasonable to expect the old lady to be on guard in every store, with every machine, or to expect the store to take basic precautions with its equipment?
To put this in gun terms, what you guys are advocating is the equivalent of letting a gun maker whose weapon explodes with standard ammunition off the hook for injuries. After all, we all know that guns sometimes explode, and that there's a chance of a faulty gun. We can also choose not to shoot if we don't want to be blown up. Would you be alright with that outcome?