What goes wrong in commercial premises specifically
A commercial site is not a factory and not a home. The risk is concentrated in a few hours and a few doors, and most of it walks in through the front.
The out-of-hours window
Almost every commercial loss happens when the premises is closed or nearly empty. That is a small, well-defined window — which is exactly what a time-bound detection rule is good at covering.
The back door nobody watches
Fire exits, service corridors, terrace access and the shutter behind the building are where entry actually happens. They are also where cameras are most often pointed at a wall.
Internal shrinkage
Stock rooms, cash points and store cupboards account for losses that never look like a break-in. A zone rule on a stock-room door during closed hours logs every entry without anyone being accused of anything.
Nobody owns the system
In an office the CCTV belongs to admin, IT and the landlord simultaneously, which means it belongs to nobody. Alerts to a named phone fix the ownership problem faster than any policy does.