Although I'm stilll "in" but inactive, I do make an effort to let others know about what I have been a part of. I only do that if the conversation leans that direction in some way.
I hated informal witnessing in the past, but I tried to do it at times because I thought I had to. However, I avoided it as much as I could.
It was actually an informal witnessing conversation though that aided me in going further to find out the truth about the "truth". I was already doubting and so my defense regarding my religion was weak, and I knew it.
So now I feel it is good to anti-witness because it feels like a release of the things I have been taught and no longer believe. It doesn't involve pushing anyone to join any crazy religious group. But it certainly makes them aware to stay clear, especially if they were already suspicious or doubting, of the JWs.
CoC