We all love our guests... but there are some that don't always love us back. Sometimes it's useful to flag these guests so that we'll be reminded of what happened if they come for another visit.
OwnerRez provides a way for you to tag a booking, and thus the guest, as having had an issue during their stay that might be relevant in the future.
There's a checkbox you can use on the booking (Overview > Notes > Change) to flag general problems with the guest. If selected, that will mark the booking as a problem booking.
You should then fill in the Notes field with reminders about what happened. On future inquiries and quotes, when the repeat guest badge shows up, it will be colored yellow and show you that there was a problem with that guest on a previous booking.
Here are two side-by-side pictures of how it looks with a normal repeat guest and one with the bad badge showing:
Note: OwnerRez does not provide a way to block problem guests from making future bookings. That couldn't be reliable anyway - people change their email addresses, phone numbers, and credit cards, and many people have the same name. This is just a way to try and give you some warning.