We walk to the store a few times a week after the school drop off. It's part of our normal routine and my parents know that. I include that in my general permission form...along with visiting the park a few times a week and the zoo in the summer (zoo is 1/4mile from my house, we walk). I'd go nuts in the summer if I had to get a permission slip for every single outting as we are out of the house every day.