Re: Don't be their 'rogue engineer'
Making copies of such emails to take with you after you quit / are fired could be used against you, if they contain anything the company could possibly consider confidential or proprietary - even a code name or (at the time) future product.
Good point, that's why you should never open the physical envelopes after you've received them, and in case of dispute be talking to legal council asap. As for that specific email, I dumped a copy at the time because I found the email interesting and I had a feeling something would happen. The email was my personal evidence that, in case of legal dispute, our email archiving wasn't as immutable and reliable as the company made it out to be. I never let on I had an actual copy, my referring to the email with the correct time and allusion to contents was ascribed to a good memory :).