You bet they do. You can buy license plate covers here in Illinois but if you use one you will get a ticket! You can also put anything you want dangling from your review mirror, but they can use that to stop you and check the rest of your vehicle because the law state you are ubstructing your vision! Just because things are legal in some states doesn't make it legal in others. Pennsylvania is the toughest state AFAIK about trailer towing, so be careful, Tony! BTW, I have been towing through there for the last 9 years going to Carlisle with nary a problem, now where is the wood to knock on.....