I would honestly have to say that it depends on the responses you get on the phone. Q: Do you live in Vegas now." A: we live around. Q: around where? A: all over. If this little bit of simple dialog starts to give you the creeps and you feel that this is not a genuine call, don't show the property. Everyone lives somewhere. The might live with relatives or be in the military in Afganistan, but they do live somewhere. If you can't get simple information out of the buyers, don't waste time with them. Another clue is if you ask "How many bedrooms are you looking for and what pricerange are you comfortable with? These are not open ended question, but questions which beg for simple answers. I am always suspicious of people who say it doesn't matter how many bedrooms or what price. Everyone knows how many bedrooms they need and what pricerange they are able to work with. So, rule of thumb simple answers to simple questions and they can view the property. When they can't think of the answers, they are not a genuine buyer. So, don't bother with them. They may not even be a genuine looker. They may be criminals casing someone's home to see what they can take at a later time.