The positive Battery cable comes off while driving - It is not attached with lugs. on 2005 Mercury Mariner

Cable slips off every time driven - Car runs till arrival
but will not restart - the cable has slipped off.
Have to push it back on and reset clock/radio/etc.
If it grounds while driving - could be serious. Dealer
Coudl'n care less - says not recalled.

Asked by for the 2005 Mercury Mariner
Any competent repair shop shold be able to make a simple fix and it shouldn't cost much. Even a auto parts store could probably assist with this repair.
How is it possible, or legal, to not bolt-down a battery cable?
Any competent car maker or seller should have "prefixed" this slide-on cable design. They don't know it's wrong and dangerous?
Your wife could have been driving and been stuck at a mall.
The car could have caught fire.
Buyers should be warned by a recall.