oh jim!! we have a UPS so that that doesn't happen to us. and with luck the generator comes on before the UPS runs out of power...
I am, unfortunately, going to have to track loads of phone cables under the floor to find out what numbers they connect to as whoever plugged them into the switch way back when didn't label them and now they want to power it down, but to do that they need to make sure that they aren't cutting off a service. gah...