I've done it in the UK (three times) by failing to notice my contactless debit card has not been accepted and walking off with the newspaper/sweets etc. (I've g

I've done it in the UK (three times) by failing to notice my contactless debit card has not been accepted and walking off with the newspaper/sweets etc. (I've gone back later to give them the money, but this is seems surprisingly difficult for a large store's systems to cope with.)