Routine service and maintenance doesn't require net connectivity to schedule.

Not all issues are routine.

So we schedule service, and then we throw away all the food anyway because the problem cannot be addressed remotely.

Agreed. I was just addressing that it's not exceedingly rare to need to get a tech out on site to address something. Should the manager be on top of this, checking temps on all the cases every day? Absolutely, but I can see the argument for a more automated system of monitors/alarms that can get a tech dispatched before the manager has even noticed the problem.