In PFSense routed needs some tweaking to prevent RIP announcing any internal networks. To do this line 92 in /usr/local/pkg/routed.inc needs the "passive" tag added:
$ret .= "no_rip_out no_solicit no_rdisc no_rdisc_adv passive";
This means that when /etc/gateways is generated any interface without RIP enabled won't be announced to everything.
The long term solution to this is not to use RIP!