Old RPG nick aside, I'm an American so I think my comment would be more self deprecating on a country wide scale. Having grown up around a family business I stopped being surprised at what wouldn't be stolen out of a retail store. I live in a farming area with many 'on your honor' farm stands. Take produce from the stand and leave money in a coffee can type setups. People steal the money cans on a regular enough basis. For these reasons and more I couldn't imagine letting people scan their products when they put things in a cart and it not being massively abused. I'd be overjoyed to be proven wrong.
I agree with you on the self checkouts. While they're sometimes quick for a handful of items, If it's more than a few items then you should get a discount equal to an employee's wage. BUT I'm all for scanning an object when I put it in the cart and just paying for it when I leave, no double handling of products by putting in the cart, taking out to be scanned, putting back in the cart. Almost walking right out the door after finding what I wanted was very quick.