I am a teacher and we don't use those in our school system and here's why: They could pose a small threat to your child at the school. Police in our town have suggested that they don't like these because a child molester or kidnapper, etc. who is watching your house or car, etc. knows exactly where your child goes to school with one of those on your car. That leaves the school open for the person to go to school to abduct your child. If the school is not careful when a person comes in to check out your child early or to pick up your child from the car rider line, etc., the person could pose as an adult who is there to pick up your child. He or she could say, "I'm a friend of your mother's. . .she couldn't come to pick you up because she has been in an accident. . . or something like that.
I also have a problem with those stickers that people are putting on the back of their vehicles that have a picture of the activity the child is involved in, say like a football with their jersey number with the child's name. A person could come up to your child and even call them by name. The child may think the person knows him or her because the stranger called him or her by name.
Some of you probably think this is stretch, but I feel it is better safe than sorry.
Angie