the background of the code you may like to keep in mind:
Last year there were huge number of specific person's personal information
posted all over 2ch. The poster used lots of Japanese IP addresses from
free VPN (www.vpngate.net). It resulted number of ISPs regulated.
AirRock-san and others had to mail lots of ISP to warn the VPN gate user
to stop using VPN acting as open proxy.
So, Tohru-san introduced the code to stop the posting from the VPN gate.
If Code-monkey-san can come up to better code, that is fine but
just removing the code may result massive personal information posting again.