Since cups-1.7.0, printers are now shared using DNSSD. The print/cups-base and print/cups-client ports offer AVAHI and MDNSRESPONDER as alternative implementations of DNSSD, with MDNSRESPONDER being enabled by default. The print/cups-filters port, which provides cups-browsed, offers only AVAHI which is disabled by default. As a result, printers advertised on FreeBSD servers are not visible by default on FreeBSD clients. Now it is possible to see them by having the clients poll the servers using the CUPS protocol, but this is a kludge and not practical in a large environment. Either print/cups-filters should have MDNSRESPONDER support added and enabled, or AVAHI support should be tested and fixed and enabled in all three ports.
It is possible to make a warning in the cups-client and cups-base ports or a comment in the description of the port-dialog? So nobody could overlook it.
I believe bug #196806 is another instance of the same (or a very closely related) problem.
In ports r410825 the MDNSRESPONDER option has been removed and the AVAHI option has been enabled by default in both cups and cups-filters.