If a client tries to book a group event for which they already have an active booking under the same email address, the system will automatically prevent the duplicate booking.
In this case, the client receives an email with the subject "Double Booking: [Service Name]", and the new booking will not be added to the specific event - only the original booking remains valid.
If an Additional Booking Is Needed
If a client has a valid reason to book a second spot (for example, booking on behalf of someone else), they can contact you directly by email and you can manually add them to the event.