Funny, I had been reading this post a couple days ago, went to Walmart yesterday and a gal had a little pup in an enclosed dog bag in the grocery dept. Of course I had to look at the little cutie.
I think when they are enclosed like that, is alright, although I don't do it. I have taken mine in a bag in the garden dept and to the dog suppy area, but not ever into the food section. I just don't believe they should be around the food.
The place I see the most dogs (besides petsmart) is Lowes. People even walk their dogs in there on a leash! I live in a retirement community, so a lot of us old foggies take our dogs with us places that we know are welcoming.
Also on this note. My vet warned me many years ago to NOT take my dog into a pet store unless I carry her in a bag or my arms. He said you just don't know what other dogs might be leaving there.