They're expressing themselves and their personality, even though there is no risk in having sex over a telephone. The recording on the line says you should not give out your home phone number or address. You can lose track of time and be in the last moments when you're cut off. So people give each other their real numbers. I have met three or four people that way.
People have a variety of attitudes towards safety, especially people in their early twenties.
They seem to be more cautious. Some of them have never entertained the thought of fucking. When I was in my early twenties in San Francisco, you either had tried it or were going to try it. My first reaction when I heard about the HIV-Negative Support Group in Boston was that it was a silly, superficial thing. We're all clean.