And while I agree that we take calculated risks every day, we need to weigh the benefits to the risks, and frankly, I see no benefit in letting my two daughters shop an aisle away from me where I can neither see nor hear them. That is not is my comfort zone and as far as I am concerned, there is no benefit that would outweigh any risk.
We will just have to agree to disagree, because it is the way that my family chooses to live in virtually every aspect of our lives (allowing our children MANY freedoms). And we'll never change, and we'll be just fine.
ETA: I'm only addressing the "danger" subject. I would never tolerate my children running and screaming and putting things in carts. I have been fortunate that by about the age of 4 all of my older ones are quite well behaved in stores, are calm and quiet, don't interfere with other people (other than to say a friendly wonderful HI!!!), and won't sabotage or damage anything. If that were not the case, they would be safely ensconced in the cart or at home with daddy.