That happened to me when I was there cleaning. I stopped working and showed them around, oh well they wasted 20 minutes that could of been spent. It was hard for me to tell them no you can't see it, so I get it. What if they had been the one.
What I did is show them around politly and then gave them my email address. Told them to mail me if they are interested. IF they had I would of sent them my questions. I did mention I needed a 700 credit score.