In Colorado you can put it in your pocket to the camp/truck on the first trip. It's so you won't tear it off during the trip. Once you get to camp/truck. You have to attach it. It's in the regulations.
I've been doing this for too may years to get it wrong. I've never gotten a ticket, because i'm careful, and if i'm not sure. I ask the warden, or call the DOW. There's no reason to not know the laws.