According to a JW witness friend of mine it is not always necessary to go to the elders to confess, not even the more serious sins such as immorality.
She said the only reason one would go to the elders is if they feel they no longer have Jehovah's favor. The elders are there to help them see they can still be loved by Jehovah.
Is she on crack!
I had a long discussion with her yesterday about religion and JWs. It was pretty interesting.