A completely unattributable friend-of-a-friend-of-a-friend thing, but I thought it was too funny to pass up:
One of my co-authors on the paper sent me exactly one email, that is to say that he should be included in the author list. And this was only in response to an email to which I attached a version of the paper which did not have his name on the author list.I don't know of any of the people directly involved (have never even met them, in fact). Guesses are welcome but I'll probably deny it anyway if you get it right! Actually it might be amusing to hear now common such behaviour is.