This title on a Reuters story on Yahoo gave me a double-take:
Ex-Heisman winner Troy Smith arrested on DUI and drug charge
There is no suggestion that the Heisman trophy award was ever rescinded. I think in my dialect, once a Heisman trophy winner, always a Heisman trophy winner. I've never heard anyone called an ex-Nobel Prize winner. Am I missing something, or is this really unusual usage? I think even O.J. Simpson is still a Heisman trophy winner.
But I can imagine that the line between where I clearly use ex- and where I don't might not be sharp. Ex-president, ex-spouse are clear. (Hmm, there's also 'former' in competition — that's what I would use for 'department head', not ex-.) I find myself sometimes starting to say "Some of our former Ph.D's (never ex-!!)", but then I usually stop and remove 'former'. Aha, they're our former students, but not our former graduates – they're our graduates forever.
But back to the Heisman trophy. Even if you only hold possession of the trophy for a year, actually or symbolically, you're still a trophy winner forever, aren't you?