Idea du jour – paperless receipts

I had a thought the other day as I was handed a massively long till receipt for one book, that all the millions (billions?) of paper receipts given out in this country, and indeed across the world,

The idea is simple:

• Link your debit/credit cards with a mobile phone number/email address
• Buy something
• Instead of churning out receipts, you get sent (instantly) a text or email or both
• Saves paper, ink, etc.

This has the added benefit of being alerted instantly if your card is being used without your knowledge (depending on how the back end works, I suppose).

For cash transactions, I can only think of tying it to loyalty cards. And who actually checks their change against receipts anyway?