Created attachment 56416 [details] Screenshot of how message displays in OPAC If a user sets up a BOR_NOTES authorised value with a staff and OPAC description, and then uses the Add messages option in the /cgi-bin/koha/circ/circulation.pl screen, when the message is viewed in the OPAC only the staff description displays. If a message in the messages database table is given a message_type of B, then the OPAC description should display.
Created attachment 56417 [details] Screenshot of BOR_NOTES authorised value policy
I think it can't work that way you suggest as the AV here is only used to provide templates/pre-formulated text snippets here that are copied into the messages field. They can also be changed before saving. The OPAC then displays the content of the messages field.