An Australian school recently put a ban on all cartwheels, handstands, somersaults and other gymnastic tumbles during recess.
Why? School administrators say that a child might get hurt performing these gymnastics without proper supervision. (It is a wonder how any of us survived recess as kids.) Fortunately, some parents have raised such a stink about this, that the rule is under review.

Why? Parents say that their children might become frightened or get discouraged by facing pitches that they can't hit.
http://www.usatoday.com/news/world/2008-08-26-australia_N.htm?csp=34
http://www.nhregister.com/site/news.cfm?newsid=20089039&BRD=1281&PAG=461&dept_id=635049&rfi=6
http://www.washingtonpost.com/wp-dyn/content/article/2008/08/25/AR2008082501687.html
I apparently lived a very dangerous childhood.