Hi David.

The Booking Start Date notification trigger fires for each learner enrolled in the seminar event. If the recipients you suggest were added to a notification that is based on the Booking Start Date notification trigger then they would receive one notification for each learner, which I'm guessing isn't the intention of your request.

If instead you'd like to be able to notify those recipients about an upcoming seminar event, with just one notification per event per recipient, then I suggest the creation of an "Event Start Date" notification trigger. This could be used to send notifications to any of the recipients you mentioned, and could be scheduled both before and after the start of the event. A corresponding "Event End Date" notification trigger could be useful as well.

Nathan