Handling recipients on scheduled blasts
Blasts sent to event RSVPs
Future RSVPs will be added to the recipient list for scheduled email and SMS blasts (right before the sending actually occurs).
Blasts sent to group members
Same as above, for the final recipient list of scheduled blasts will contain the latest group members at the point the sending occurred.
Similarly, if the blast recipients are determined by a filter, then the final recipients of the blast will be those people who match the filter at the time the sending occurs.