Interesting.
I wonder how this will work in reality. Its Friday evening, there's a queue with one person serving. You present your six bottles and explain the wine is currently £0.50p cheaper in Sainsburys. Then what? They take your word for it?
I guess someone will need to either make a call or go online, but what if the discount is regional and not advertised on their website? CoOp sell the same wines at different prices all over the country, my four local stores rarely share the same price.
It could get messy, I may put it to the test
