On several occasions in the past it has become public because the office is the only party that's required to keep things confidential. The MP or senator is free actually. There is no bar against the complainer from making a complaint public. Also, if the media finds out about it, there's no bar against them from making it public. We're the only ones who are required to keep it confidential.
What I was proposing as a possibility, which would have to be looked at very carefully, would be to impose a general blanket obligation on anyone involved to keep it confidential.