Here in PA we have such vagueness in our law we can carry almost anything concealed or open (no autos or daggers and in Philly not even a SAK). That said, if you find yourself on the wrong side of the law that knife that was legal can become illegal real quick. That said, schools are a very clear no go. Thankfully we have a very good gun law (still no go at school) too. In fact, with my license I can carry my concealed gun in Philly but not a SAK. Go figure.