Primary v. Secondary
As with many laws, including seat belt laws and open container laws, enforcement is either primary or secondary. If it is a primary enforcement law, that means you can get pulled over just for violating it. If it's a secondary law you have to also break an additional law before you can get cited. In nearly every state with a full or novice ban this is a primary, and not a secondary, offense. Washington is the only state with a full, comprehensive "secondary" ban.

Photo Credit: TimCaynes