State knife laws are comically vague and are more about carrying a weapon. They definitely need clearing up and possibly preemption.
I carry a pocket knife pretty much everywhere. I don't carry it as a weapon, I carry it as a tool. If questioned about it that's how I'll respond.
Funny story: Decided to go visit the Liberty Bell on my way back from the east coast. I was carrying my Doug Ritter Griptilian with an Orange handle. Went to walk in and at the metal detector I was emptying my pockets and realized I had my knife. As I had it in my hand about to ask if it was okay to bring in a security guard said, "I'll take that," and grabbed it from my had.
I said something resembling, "Like hell you will, I'll just go put it in my car," and they tried to walk away with it like it was theirs now. I was able to quickly get a supervisor's attention. He came over and I explained they definitely can't keep it but I carry it as a tool, not a weapon. The supervisor took it from the guard and said to him, "What's he going to do with this?" and handed it back to me. I apologized for the trouble and thanked him for his rationality.