AHAHAHAHAHAH got a funny story for that!! I used to do mobile dog grooming, I had the cute little magnets on my car, a lady was coming up along side of me, she crashed trying to write down my phone number and drive at the same time. Needless to say, I didn't get her business 8)
Just a heads up: I was told by my insurance company that if you have your biz add on your car you have to register it as a business vehicle on your insurance, which is more than if it were just a personal vehicle. If it is listed as a personal vehicle & you get in a wreck w/ the magnet, sign, etc on your car... you'll be in great trouble. Not sure what that means, it may vary from company to company.