In my case I told them myself of what I had done. They asked if I had used a condom to which I replied "no". So it was just my confession alone. But I know they did still use the two-witness rule at that time.
Their response was that since it wasn't pre-planned and the result of "being in the wrong place at the wrong time", they weren't going to DFed me UNTIL they gave me the ultimatum to kick the person and their boyfriend out of my house. Yeah I did a bad thing. But I decided not to heed their advice and told them to stick it. I also told them I wasn't convinced that JW's had the truth because of the overhwelming evidence of a lack of real love and only a strict adherence to rules (like the Pharisees).
That didn't go over very well.
I didn't care. My "worldy friend" forgave me and we are still friends (20+ years) to this day. I'm also friends with the woman (his exgf).
Since then, of the 300+ witnesses I knew, I have only spoken or met a handful, except when I go to the Memorial to partake (just to piss the Elders off) and speak to the other DFed people there (to further piss the Elders off).