"The short version is that he now has to pay a fine and have a record because some high-school girl freaked out about seeing a knife that does not violate any federal statue for pocket carry."

The fine is probably trivial. More serious IMO is this talk about a "record". If this is considered a criminal violation then I suggest he get an attorney. It is not out of the realm of possibility that one day your state legislature passes a law that says that anyone convicted (read "who pleads guilty") to a weapons violation is prohibited forever from carrying a concealed weapon. Then your buddy is out of luck.

Odds are an attorney will be able to plea bargain it down or maybe even make it go away entirely if the prosecutor decides it isn't worth pursuing.

Regards, Vince