Did the number of thefts go down, or did it just change where they get stolen?
Not sure - just know that there were a spate of car thefts [from driveways] in my community because people left their cars unattended. After the law - none in my area ...
FYI:
Just the other day, I pulled into 7-11, got out and locked my car [like I always do]. A car pulled in right next to me. Driver got out, apparently left the car running. While I was getting coffee, I looked out the window to see 3 "upstanding citizens" climb in the idiot's car and drive off while he was paying for his purchases. 'Course, he tried to run and catch them ...