Appointment confirmations and reminders get the automatic "Reply STOP to unsubscribe" line and sender name, on the first text and again every 30 days. For a client who just booked, that reads like marketing, and if they reply STOP they also lose their reminders. We'd like to mark a workflow's SMS step (or a calendar's notifications) as transactional, so the automatic line isn't added there, while it stays on for marketing texts.