A broken/smaller whip is  more potent at causing injury than the  buckle or buttons on out side of shoes. How ever , surprisingly, rule book doesn't say anything about  minimum length of polo whip. It is easy to miss out on this aspect because  of all the mounted sports , its only polo that requires such a restriction.  Most of the sports involving horses like Jumping, Dressage, Eventing, Tent Pegging etc are content with specifying max size. However, when it comes to polo , it becomes necessary to spell out  minimum size as well. Especially because unlike all other disciplines, Polo involves getting into physical contact with other players at a gallop.  In such times  this  innocent looking smaller or broken whip poses a serious threat to  other players . It can cause considerable damage when poked unintentionally into another rider's ribs , thigh , groin (ouch) while two riders are  engrossed in competitive ride off f. So far we have just analysed unintentional accidents.  With  element of "Intention" coming into play, scope and severity of injury can increase many folds.

Crisp summary of IPA Field  Rule No 3,4 & 5 are as follows

• Rule 3  - Disqualifies blind, bleeding and lame pony. Also disqualifies a pony to play for two teams in same tournament( 10 goals or above).
• Rule 4 - Prohibits side blinders
•  Rule 5 - Prohibits pointed spurs, excessive use of whip , use of whip on other player or pony (Though  "Hitting with mallet" not being  mentioned specifically can give ideas to some players)