Although such items can certainly be terrifying, in this particular case an appellate court in New Jersey decided that throwing one at a corrections officer did not constitute "attempted assault with a weapon."
According to the report (thanks, Robert), Gerald Lovelace is currently serving a prison term in Bayside State Prison for some other sort of weapons charge. After his wife visited him in 2012, an officer noticed that he was wearing a wedding ring, an item that inmates are not allowed to wear (not sure why, but I can think of a few good reasons). The officer demanded that he turn it over, which he did—by taking it off and throwing it at her. A hearing officer ruled that this was "attempted assault with a weapon," and Lovelace appealed.
The appellate division found this to be a pretty easy case, given the administrative code's definition of "weapon," which is "anything readily capable of lethal use or of inflicting serious bodily injury." This includes (but is not limited to) firearms, knives, and "billies, blackjacks, bludgeons, metal knuckles, sandclubs, slingshots, cesti or similar leather bands studded with metal filings or razor blades imbedded in wood...." That part is based on New Jersey's statutory list of prohibited weapons, and I'm sure that like me you now have two main questions: (1) does this mean I can't bring my cesti into New Jersey, and (2) have I been using the wrong Latin plural form of "cestus" all this time?
The answers are (1) yes, unless you have an "explainable lawful purpose" for possessing one, and (2) how am I supposed to know what form you have been using? I have enough to do without following you around and checking on your noun declensions, pal. But I do think the state department of corrections got it wrong, and so has included girdles on its list of dangerous weapons.