Sad. There's a lot more to walking your dog than just the "walking" part.
Not only does walking your dog help him get fresh air and light, but it also gives his
nose something to do, too. Imagine staring at the same bit of wallpaper all day every day; keeping your dog indoors is doing pretty much the same thing to him.
I get that the woman in the picture is (likely) just minding the dogs. However, whether you are a dog owner, or a dog minder, you owe it to your dog(s) to take them for a walk. While I'd like to think the treadmill is meant
only for when the weather is too bad for walks, it has "path of least resistance" written all over it, and we all know what happens when people are given an easy out like that.