I needed to pick up some things at the supermarket this weekend, but I had forgotten my lock. I just wheeled my bike around and picked up what I needed. i got a few stares, but really, what's the difference between a bike a shopping cart? I don't think bringing your bike into Home Depot would be an issue either.
Like an earlier poster, when I lived in Redmond, WA I would often walk my bike into any store that didn't have bike parking - such as the Office Depot nearby my apartment. Some places, however, are too nice. Like any place with carpet - I feel weird about that...