Segments
A saved question, not a saved list: who matches right now, every time it is used.
A segment is a saved question — "stayed twice and has not been back since June" — not a saved answer. It is run when you use it, so the members are right on the day, and anybody marked do-not-email is left out every time, with no override anywhere.

Do this
- New segment — a name, and conditions from the closed list: stays, nights, revenue, last stay, lifecycle, tag, city, company, and whether we may write to them. There is no free-form expression to get wrong.
- The list. Pinned segments are the ones the Today tab counts.
- Press one and its members as of now are listed beneath, with Export CSV for whoever sends the mail.