This is interesting. I have been toying with the idea of keeping cash in the house 'just in case', but I don't know what a week's supply would mean, and I'm not even sure how I would spend it. Currently I get out £100 when I go to the cashpoint, and it can last for months, as I use cash so rarely. My groceries are delivered, and most of my other shopping is online. I don't suppose the delivery people would take COD, so there wouldn't be much point in that.
I'd be interested to hear others' views on how much would be a sensible balance between having enough and too much cash lying around, and on what they would be likely to spend folding money in 'emergencies'.