Can We Walk Through The House Alone?

For the first time in the business we had a buyer ask if they could walk through the home we were showing them alone. This was the 2nd showing of this home and on the first day the husband was unable to be there. The home was vacant and this was a higher end home. Now I know what your thinking, were they looking to steel something, to scope the place out? No, this was a very nice couple that I think just wanted to walk-through the home and be free to talk over all the pros and cons of the home. Of course we stayed right outside and I did go in after a bit to check on them, But I have to say, it was a strange request for us. So my question... Have you been asked as an agent to "View" the home alone? Maybe some buyers don't like an agent following them through every room of the house?