Ketchup
French school cafeterias have a nationwide ban on ketchup. Why? Well, not only is it filled with sugar, but they believe that the children need to become more aware of French cuisine. Therefore, Ketchup has been banned from school cafeterias in an attempt to have the kids learn about French food and French food only.
#5 cost of removal disposed chewing gum tens and hundreds of millions annually, so...
#3 ketchup has no room in schools, however you look at it.