Like most pop-culture conventions, New York Comic Con has a fairly extensive weapons policy -- one that prohibits the obvious, like functional firearms (yes, BB and air soft guns are included) and, perhaps, the not so obvious.
Under the heading of "obvious" also falls firecrackers and fireworks, chemical weapons, any kind realistic firearm that could be mistaken for a real one, sharpened metal-bladed weapons, brass knuckles and the like. Less obvious, and sure to complicate more than a few cosplay plans, are functional longbows and crossbows, clubs, water guns, nunchaku, whips, and "hard prop weapons" made of metal, fiberglass and glass.
It's all there on the NYCC website for everyone to read. However, not everyone has done so, as USA Today's Carly Mallenbaum illustrates in a Vine video (below) of all the weapons confiscated on Friday alone. In the snippet, we glimpse what could easily be mistaken for the aftermath of a police raid: tables covered with a crossbow, bows, clubs, realistic replica guns, and enough katanas to arm a small army of samurai. It's a pretty impressive haul, as these things go.
They're all labeled with green tags, which I presume means means the owners can reclaim them at the end of the day, in time to be reminded of the final sentence in NYCC's weapons policy: "Basically, don't be an idiot."