Way back in another life, I worked for a freight airline. Our data center had backup generators and a filtered power supply made to handle interruptions. Once a month I could look out lunch room windows and see black diesel smoke rising up from the monthly test of the backup generators.

Even the best plans can go awry. If my feel for Delta is correct, they will fix this. If not, well..... TripAdvisor just announced its list of best and worst airlines. That can always be updated.