Most of FreeBSD's i have are servers without X11 or any desktop environment and as i know from previous Linux situations many informations are outputed on the console tty, so you kinda need to have a monitor turned on and mandatory have to be present there to read it... so FreeBSD has a very nice way to help us: /var/log/console.log!
It's not enabled by default but:
# touch /var/log/console.log
# chmod 600 /var/log/console.log
# vim /etc/syslog.conf
And uncomment the setting: console.info /var/log/console.log
# /etc/rc.d/syslogd restart