The 6-year old was under 60 lbs. (the minimum for using a tazer). The 12 year old girl was ditching class, a situation that hardly warrants a major use of force.
It sounds like the Tazer's were viewed as a new toy by a couple overzealous members of the Miami PD.
Wonder what blame would be assessed the officer had he allowed the out-of-control and drunken girl to dash across the street to be flattened by cars?