Martin, you say that FMV will make you grow a third ear like that's a BAD thing. I am about half deaf now, so maybe this will help.
Five of my trees (I only have 15) show signs. I figure it's only a matter of time before the rest do also.
From my experience (which is limited), and from what I've read (which is a lot), FMV is a fact of life for most of us, and there's not a whole lot to be done about it. The good news is that most of the time, the trees appear healthy otherwise and they still produce.