For what it's worth, I was allowed to fly on the JS on Alitalia a few years back... I had purchased an ID90 and couldn't get on, so the agent offered me the JS instead. I got to keep my ID90, so it was a freebie.

A friend of mine successfully did the same on Finnair a while back. Mind you, that was before 9/11 - not sure how that would work out these days...

Best of luck!