Legalize what is in that picture, and pedophiles all over the world will strive to become a teacher. That means other good teachers will all lose to competitive pedophiles and lose their job. This will result in increase in unemployment rate, civil unrest, and decrease in the overall happiness of American citizens.
Kids are humans, and they are capable of understanding what is right and what is wrong. I am strongly opposed to education that puts too much focus on the carrot and the stick (and yes, that means I'm also against teachers rewarding their students too much). Juicier carrots and tougher sticks don't make students better people. They make them robots which respond to stimuli instead.
'If the people be led by laws, and uniformity sought to be given them by punishments, they will try to avoid the punishment, but have no sense of shame. If they be led by virtue, and uniformity sought to be given them by the rules of propriety, they will have the sense of shame, and moreover will become good.' (Analects 2.3) That was on ruling, but it applies to students as well. We need students to understand why they should be good, and they'll be good. For example, we should let them know it is their filial duty to excel in exams and thereby make their parents proud. That will drive them to work hard without using physical punishment.