I'm a member of my local YMCA and a good friend of mine works there. About a week ago I stopped in my way out to chat about life, nothing specific.
She knows I'm transitioning but was keeping my secret because last I talked to her about it, it was on a need to know basis
Anyway, after I left, a co-worker asked her how long I had been transitioning. She didn't know what to say and finally broke down and said yes, but that she didn't know how long.
She was all nervous telling me which I quickly put to rest.
I just thought it was funny. But that is the first person I know of that flat out guessed and said anything.