Self-check out as a Family Affair

At the library we have self-check out machines so people don't have to wait in line to check out their books. They can do it themselves. Today a family gathered around the machine with their library cards and books. The mother scanned the card. The youngest put a book on the scanner. When it scanned, the oldest picked up the book and gave it to their dad. After all their books were checked out, the middle child took the receipt. So everyone got to do something.