During the installation process of the 10.3 release, the FreeBSD Installer was unable to find my hidden wireless network during the network interface configuration. I was told I should submit a bug report on this despite being able to fix it through the wpa_supplicant.conf file afterwards due to it potentially being a problem for newer users not experienced with manual configuration. The wpa_supplicant.conf that the installer created was empty so I solved the problem by adding my network in this format: network={ scan_ssid=1 ssid="mywpa" psk="mypsk" } This information was NOT available in the handbook and I stumbled into it by accident on a 3rd party blog here: https://srobb.net/fbsdquickwireless.html.
Fixed in r309716.