I agree this could become a problem. But don't forget that one of the most pressing issues we face is an aging society. In Europe it's even more severe than in the US. We will need a large number of people who care for the elderly.

Hey, and instead of noting and then punching in product numbers, couldn't we just scan the numbers using the phone camera and press OK at the checkout to have the amount appear on the next phone bill? I'm sure something like that already exists.