Is it really illegal to own a switch blade but legal to purchase and own assault rifles?
I've been doing some searching on why switchblades are illegal (your post sparked my curiosity) and can't seem to find a good reason other than 'politicians are scared of whatever hollywood villifies'. It seems all the interest in switchblades faded after they became illegal, so there was no lobby to bring them back into legality. Nunchaku and Nightsticks are also illegal in many places.
I'm not kidding. Read Massachusetts GL 269S10: http://www.knifeup.com/massachusetts-knife-law/