I believe Michigan ranks as the worst state in regards to automatic Knives. Possible 4 year felony to even have one in your home. Obviously not fully enforced, but it is on the books if caught with one. I hear in Florida you can walk around in public with a switchblade between your teeth.....legally.

P.S. Michigan, does allow anyone (non felon) to walk into Walmart with a sidearm on their hip.