The way I see it if the guy is legit he will be on every stupid talk show being interviewed about why he was packing. If we never see him again he's probably an undercover agent being used to further the anti gun agenda.
The website listed on his sign was this
http://www.freetherepublic.com/
I thought it was great that the three reporters were speculating that the scene could turn vilont because someone with a firearm is involved in a discussion with people with opposing views. Apparently just owning a handgun makes you ready to kill if someone disagrees with you. Awesome!!