[Koha] Paying fines (again)?

(Koha 3.0alpha, (Gentoo) Linux 2.6.24, MySQL 5.0.56) I appreciate all the help over the last few months. We're about launch our little library here at church, but I just wanted to try this question once more: Is there any way to have Koha tell the librarian, either during a check-out or check-in, that the current patron has a fine on his account? If it's a check-in, the patron may want to pay the fine right away. If it's a check-out, we want to disallow the checkout (no further borrowing until the fine is paid). I'm sure there are existing Koha sites that do this kind of thing, right? Thanks again.