It would be very useful to be able to view attendees of previous booking. We like to send a follow-up email to folks who have attended our events (with a PDF attachment, so this can't be sent automatically through your app, we must do it manually), but currently we can only view the up-coming bookings. There's no way to look back on who has attended previous events on the basic plan version (not pro version as I realise this may already be a feature there).