I carried an auto in Montana for a long time, which is illegal. When I was 19, I got pulled over for speeding one night and was given a breathalyzer, as my passenger had been drinking and they could smell the alcohol. Before having me blow into the machine, they removed my knife so I couldn't kill all 4 officers with the 2.8" blade (I know, only being safe). Once the officer pressed the button, he looked at me and said "uh oh". Turns out, you can buy them and own them, but you can't have them on your person.
I was arrested and taken to jail. I was booked and placed in 4-man cell with 9 people in it, the lot ranging from DUI's, to bar fighters, to homeless guys looking for a warm place to crash for the weekend. The smell was unbearable, and the conflicting attitudes were even worse. I spent 24 hours in there before caving and calling my mom to bail me out. I paid an $820 fine and forfeited the knife.
I live in Oregon now, which is one of the most free states when it comes to knives. I used to EDC an auto becaue I could, but got tired of being told "those are illegal" by people whom have no clue what they are talking about. I only carry an auto when I ski, and that's only because the blade can be locked shut, preventing unwelcome opening in the event of a wreck.
Needless to say, when I go home to Montana, I do NOT carry an auto