If you add a customer rating called Blacklist, this is treated differently form the other ratings.
When a booking is created with this rating, a warning is showing in the booking. We can't block blacklisted customers from booking a stay, but this alert will warn you or your team of past issues.
Please be aware:
The rating is automatically allocated to any subsequent booking with the same email address or postcode.
If you are collecting the money for Booking.com reservations and have blacklisted a guest which has used e.g. the postcode 0000, any subsequent booking.com reservation using this same postcode, will also, rightly or wrongly, be showing as blacklisted.