While I don't talk to everyone I know about unschooling, I've never hidden the fact that I unschool my children from people I work with. One of the really positive aspects about the work I've been doing for the past 15 years is that I get to spend time visiting customers around the country (and even around the world - Australia and England, mostly). There's often the opportunity to go out to lunch with the customer, where we try not to just talk about work, and where the questions come up about family. When asked, I usually say that I homeschool my kids, and many people are satisfied with that; some ask questions about things like grades and tests, and that's where I start getting into unschooling. (On a personal note, I find myself wanting to walk that fine line about not being afraid to defend my choices without coming across as someone who tries to convert everyone to my point of view - made all the more important by the fact that these are paying customers who could easily decide that they'd rather pay someone else.) Generally speaking, I'm talking to college educated professionals successfully employed in a corporate environment - perhaps the most difficult environment in which to defend unschooling. Sometimes the discussion at this point gets pretty deep, but often there is some level of skepticism, considering how most of us in the corporate world got where we are (e.g., going through the typical education systems from public school through college).
When the discussion turns to the background of the individual I'm talking with, it's interesting how often their degree (current or original) is in a field much different than what they are working in today, and how the part of their job that they find the most interesting and/or satisfying ties back to something they did outside of school. For example, I was recently talking with a customer during such a lunch. He has a degree in Psychology, but had always tinkered with computers (even building his own computers). He had been unhappy with his work in the field since he graduated, and a friend of his commented about his hobby "if you could find a job doing that all day, you'd be all set." Well, he went back to school and got a degree in computer science, and has been happily engaged in the high tech industry for 15 years. So, as we discussed unschooling a bit more, he came to appreciate that if he had not gone through the standard process, he would have ended up in his current field sooner, and would have saved a lot of money in student loans over the years.
Over the years, I've had many situations where I've remained in touch with customers like this over extended periods of time, and they will often revisit this topic with me. I've found it interesting to know that even though most of them are not prepared to make the change, they've discussed this issue with their spouses, and they've come up with other questions about unschooling. Part of my method for dealing with their questions is to ask them some questions in response. Two of my favorite questions back to them are "what did you learn in school before college that helps you in your job" and "what is it that you learned in school that you couldn't have learned outside of school." I don't often wait for a response, but it sure gets them thinking. Again, I'm not trying to convert them - just make them understand that there might be a different, if not better way, for kids to spend their time preparing for their adult lives.