Sparky,
It sounds like it was Energy management. This is the area that my friend has had experience with, and I only, by knowing it was there. The stores have different lighting levels for different times of day or night. There would typically be a small lighting and A/C - Heating scheme that remained on 24/7 and then a short time before opening lighting levels would change to allow clerks (associates is proper I believe) to see to stock shelves, clean etc. At opening time Light levels come up full, Lighted Display cases and all signage comes on with A/C & Heat. And then at closing the process gets reversed.
As a side note:
This Retail chain recently went out of business and pieces of the stores were liquidated. I was involved in dismantling several stores (Electrically) to get back to Bare walls and ceiling. We did this process carefully and thouroughly, making sure to cap and cover everything after removed. This was on a by the hour basis. The liquidator's Home office did not appreciate this "unnecesary" expense and tried to subvert it at the end and even withholding payment. Needless to say, in all the other stores things were ripped out, usually by the purchaser at times when power was not "up" and therefore leaving a hazard to be met when things turned back on. I don't see how the individual Landlords allowed this, but it happened.
