This is how it was done in this [0] very nice 60 years old (I'm sad now) movie. [Spoiler alert] An alarm is triggered so many times the guards just disable it. Alert fatigue has worked the same forever. Nobody wants to check the thousands of false alarms that probably happen every day across thousands of locations.
replyAs long a schedule is conceived in one place and applied in another, even with human intervention on both sides, either one of the sides can be swindled. At this point with the bar for a successful hack being lower than ever, completely removing the hardware necessary to make remote changes is probably the only way to limit the blast radius.
Maybe allowing to send the schedule but requiring a local employee to operate a local hardware only control to apply it could work, but who has the money for this kind of complexity. Something like this on every freezer (device, really) in a fleet probably costs multiples of the money they lost with the spoiled food.