There are no security issues with it. The user posting a message doesn't know its being included, only the recipient sees it and if the recipient replies, he can chop that out of the reply. I will add a setting to disable it. Remote host and remote ip is the user who posted the message ip and hostname. Hostname isn't always present. Local address is the web server ip address.
Even if the user knew that his ip address was being captured, they should expect that every web site captures it, everything is in the web logs, so there is no privacy issue about ip addresses that isn't already there.
Best,
Joe