We like to have a phone conversation early on. We've been pretty active in organizing Meet Ups! and feel it's our duty, as hosts, to at least know if the folks we're giving information to are what they say they are, most notably male and female.
We have a toll-free number we can give folks which is unlisted and can't be back-tracked to learn our address. In fact, the prefix could be anywhere in the United States and maybe Canada, too. We pay a small toll when a couple calls, but it is a very low price for what we learn.
Only after we're sure of who they are will we give the details they need to attend the Meet Up!
Mr. Alura