I built the list of email addresses for the 2016 survey announcement by taking the intersection of email addresses for Wikitech users that were both confirmed and had not opted out of mail contact and the membership roster for the Tool Labs project. I have a list of ~30 addresses that bounced. I think that we should mark their Wikitech user account emails as unconfirmed. This will cut down on bounces next year and also reduce possible bounces that are already happening for watchlist emails and other on-wiki initiated mailings.
The list of bounces is on silver as /home/bd808/projects/tool-labs-survey/2016/2016-bounce-list.txt