It's happening with increasing frequency. Vehicle safety inspectors are telling car owners to remove window decals before passing them.
It may seem like a new practice, but it's not.
"There is no legal right to have anything on the window that you're supposed to be able to see through" said Bill Green, former owner and now consultant to Shell Gas in Kahala. He says the law has always been on the books, but with new procedures and technologies it's now being enforced.
"Now we do it with a camera and we take a picture of the car…and especially that rear window is visible in the picture, and so now you're actually taking a picture of something that's illegal."
There are exemptions, however. Green says that trucks, minivans and SUV's are exempt, and CAN have decals on the rear-side and rear facing windows. Cars and station wagons cannot.
All vehicles cannot have decals on the front-side windows and front facing windshield. However, military and parking stickers are allowed.
Green said that inspectors can use discretion on allowing certain stickers in certain areas, but warns drivers not to get testy with the process.
"The whole law itself is there to protect you as you're driving down the street, so some idiot isn't going around with wires sticking out of his tires with no headlights so you think he's a motorcycle" he said.
Bill's best advice to car owners with window decals is to remove them with a razor blade before going for a vehicle inspection.