Visible crew/equipment: As Stabler is bringing Saul Picard to the cop car after finding him in the park, a large boom mic is visible in the reflection of the car's window as Stabler opens the door. (00:13:40)
Visible crew/equipment: After Picard headbutts Stabler into the car window and runs away, Benson runs over to comfort him. As she cradles him, the reflection in the side of the car shows the camera person filming as the shot gets closer. (00:14:05)
Answer: I didn't see the show so I don't know the details. A general answer would be because a reckless endangerment charge is easier to prove "beyond a Reasonable Doubt" in court and get a conviction. This charge would not require the prosecutor to prove intent, which would be required for proving aggravated or simple assault. Also, if there were no visible injuries, it is difficult to show bodily injury. Just because the reckless endangerment charge was specifically mentioned, it does not necessarily mean there were not other charges filed. Police often make multiple charges, like lesser-included offenses, so that the defendant's act will fall under one of them if the legal requirements are not met for the others, if they are not sure of the best charge to make (the district attorney knows and can decide), or to have something to plea bargain with.
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