I think it's pretty inconsiderate to the poor dog to leave him there for that long if you know you're going to be inside for an hour or two. I know it'd be torture for my dog to be by the door seeing people to play with for that long, he'd wind up annoyed and bored. I'd just leave him home.

I also think it's inconsiderate to others leaving him that close to the door and taking up that much of the path. It is a public space, but in that particular space it would be reasonable to come across young children who may a) be scared of dogs, b) be allergic to dogs, or c) come running out and do what kids do - maybe get rough with the dog and have him react. C) is what I'd be most worried about. If the dog's been there bored for an hour you don't know what a child may do and how he may react.