/diy/ - Do It Yourself

So I'm ignorant when it comes to most of Ham radio, but something I really don't understand is the how you would get caught for not having the license? It seems like its mostly an honor system thing/tax on users that can't be enforced unless there's something I'm missing.
Obviously if you just gave out your information and that you didn't have a license freely, you'd get caught. But is there any way to actually track a signal back to its source? Can't imagine it's something as easy as tracking an IP address.