No, I haven't participated in a face to face public opinion poll but over the years I have belonged to a number of paying (small amounts) internet survey sites and some of those poll public opinion, (although most are product marketing research.)
I probably have. The only time I recall was when I was shopping in the City. Someone came up to me (and others) and put a microphone in my face and asked my opinion on something. I can't remember what. The kids were only young. Anyway, the next day, I was in the Herald - Sun, along with a photo.