I have a good friend and she put me in contact with some friends of hers who I can stay with when I travel. However, I do not know these people and my friend would never put me in contact with any dodgy people and I have spoken to these people several times on the phone and they seem fine. A friend of mine was dubious saying how could you stay with people you dont know etc and I said its better to stay with people via a friends introduction than hook up with some random person online and stay with them because at least if a friend has made an introduction for you then it should be ok