If you are talking about the mussel inspection, you do need to go thru it every time you leave the lake. DNR will, and does, set up remote inspection stations and if you don't have the paperwork and the orange block, it can be a $10,000 fine, especially if they find live mussels on your boat.
An "I love Lake Powell" sticker is a great addition to any boat, but isn't a get out of jail free card when it comes to the inspections.
Happy Boating!