My current guide dog Tulia will wear her boots. The very strange thing about it though is that she does not want to sit or lie down in them.
If we are in a restaurant, she will stand for a long time wearing her boots, leaning her head on me but not sitting or lying down. I have heard that when dogs sit, they do so by sliding their feet. When wearing boots, they sometimes can't quite figure out how to do it. However, I know she knows how to sit in her boots as she can do it. If we are going to be somewhere for any length of time, I remove them and she is grateful. Never had a dog before that would just stand there in their boots. Tulia keeps them on though and that is wonderful for us both.