You have to have 'dog licenses' where I am. Your vehicle also has to have a separator between the front and the back if you're transporting a pet. It's not something that's enforced, but if you're pulled over and being a dick a cop can technically write you a ticket for it.

Similarly, the dog license isn't really enforced..it's not like there are people walking around asking for papers, it's probably more so to be able to hold people accountable after incidents and to be able to prove ownership in disputes. I didn't get one until I had to move into an apartment that actually required it.

Granted, neither of those things pose a risk to the public or the animal the way that not following leash laws does. But I suspect cops treat it similarly. I've heard about leashed dogs getting killed due to being attacked by unleashed ones. Scary stuff. People really suck.