Rant: Receipts

The other day I went to return a book, but didn't have a receipt, because I had lost it. It didn't matter that they had scanned my ID card, and knew that I had purchased the book from them only days before. Since I lost that piece of paper they charged me $10 to return it. How lame. I really don't like holding on to useless paper. Receipts are technology from before computers, now in the computer era they need to make their move out of existence and stop wasting trees. We have the information of buying things through online backing and credit card statements, which also waste trees. Why can't technology we use just work instead of letting use get stuck with old wasteful traditions.