Booking password
Sending event reservations requires that you know the recipient’s booking
password. If you add the recipient’s password to the booking password field of
the recipient’s contact card, the password is automatically taken from there
when you send a reservation.
When you send a reservation with an incorrect password, the recipient’s
communicator discards the reservation.
You can give your own booking password to those whom you allow to send
reservations to your calendar. If you do not set a password, your
communicator accepts all reservations.
Define your booking password in the Calendar settings.