I have been going to SA for over 13 years and have not been "found out" yet. Neither have any of my frum and non-frum - and for that matter - non-jewish - associates.
The problem that most folks who I meet really have with going to meetings is that they know it'll be uncomfortable. There is often some panic inside before coming face to face with a room full of recovering perverts. Oh my. I remember it still today. It's quite funny, actually: I endanger myself to get mixed up in porn and other behaviors that could eventually get me arrested and in the papers... but going into a room full of guys who - like me - have every reason in the world to stay anonymous - now that's scary!! Hah!! I can be so goofy!