Agree about not putting identifying information on your car, but you’re acting like someone that abducts kids from schools would care to target yours specifically rather than just going to any school in the area (even the one on someone’s bumper sticker) and looking for the most vulnerable child available. If a pervert sees your child playing outside your house he’s way more likely to grab her there than try to find her at a school with hundreds of kids leaving/playing at the same time