I have never seen anyone online anywhere that I knew but didn't know the were gay or bi. But I did have a friend I knew was gay walk into my booth at an ABS. He didn't know I was bi. He does now. Gave me a hell of a blow job, kissed me with his cummy lips, winked at me and left. He has never told anyone...that I know of at least. Never had a repeat either.
I have often thought about what it would be like if I saw someone I knew when I'm naked and stroking or sucking cock in my favorite ABS. That would be exhilarating and hot!