Back when I was with NYPD, the NYC Council was considering a law to slow down high school truancy. My boss was giddy with excitement. He saw it as a way to search the backpacks of HS kids. He thought that it would lead to the arrest of lots more kids. And lots of more criminal court summons. He didn't care a bit about the truancy issue.
The Law of Unintended Consequences. When lawmakers pass a law, they have to realize that the enforcement will generally not be what they intended.