iptables won’t start, just exits with no message

I was setting up a router and had no netfilter dir under ipv4 so I tried to start iptables but it would exit with no message. I debugged the /etc/init.d/iptables script and determined it was exiting because there was no /etc/sysconfig/iptables file:

 start() {     [ -f "$IPTABLES_DATA" ] || return 1 

I created an empty one by touching it and now iptables starts. Why was there no error message? Whoever wrote the iptables start script at netfilter HQ never put one in!