John, my local Home Depots and Safeways, KMart and Costco to not have parking lot surveillance. To me these big box stores likely have store wide policys on such issues. In addition these busy parking lots likely experience numerous altercations of one kind or another over the course of a 12 month period.
Therefore, it would appear to me that they (big box) have chosen to deligate any liability issues on said lots to their insurance provider do deal with accordingly. Again, to me, this implies that any increase in their insurance premiums as a result of parking lot altercations, even over a 10 year period, is less than the cost of investing in security cameras for the same period.
Let's not forget that security cameras can be a double edged sword with the very people you are endeavoring to protect ending up suing your ass because they slipped on a banana skin etc. No problem though....you have insurance and your premium still goes up due to the claim that may not have had merit without the evidence from your own camera!!!
This brings me back to: "Are parking lot cameras really necessary at all?"