For critical stuff that is not instantaneous, it's good to have both automated and human communication/confirmation. In this case, the automation is equipment

For critical stuff that is not instantaneous, it's good to have both automated and human communication/confirmation. In this case, the automation is equipment throughout the grid that can disconnect a line if it falls too far out of compliance (for example, frequency drops too low, due to a sudden increase in load). As mentioned elsewhere, huge consumers get their own substation, and such equipment can be placed there. You also have people who are drilled in following procedures, especially when failures in process become very public.