This is indeed bizarre. I've not had any reports of this on the Questia side and I've been checking each one to make sure - I did have a lost code once prior, but that's to be expected out of the hundreds we've given out. I'll look into this more, but I think we can try and cut down on the issue by advocating more use of special-purpose e-mails for it. I advocate brand new e-mails for Questia, since renewals cannot be done. The one error I had on my end has not been duplicated since.