Coles stores closed as nationwide checkout glitch causes chaos.

Imagine what it would be like in a blackout when all the stores close their doors?! 

https://au.news.yahoo.com/computers-nationwide-glitch-throws-coles-supermarkets-chaos-235054235.html

Britain Blackout 2013 - Documentary

A very interesting look at just how much the country is effected by losing just this one service.