The Stowmarket Tesco had a power failure only a week or two after they'd opened, when establishing good public relations with their new customers was obviously really important to the company.
The manager asked everyone to move to the exit (so that they couldn't put extra stuff into their trolleys) and then said "Sorry about the inconvenience. Whatever you've got in your trolleys, you can take free of charge".
The publicity probably worked well for them. Loads of people starting shopping in Tesco after that, hoping for another power cut!
OK, I admit it: I was one of them ;-)
;-)