I do think that kindergarten teachers being all women is a big problem. If I have a son someday, I would want him to have some good male teachers that he can look up to from a young age. I had one in 5th grade and it really helped me.
This did happen to me once. I asked someone to a general get-to-know-you coffee and she spent the next two years mentioning her boyfriend to me and even mentioning a couple of times that she liked me as a friend but didn't want to date me. I thought it best not to mention that my interest in dating her was equally low.