The Occupy Wall Street protests continue into their fourth day of free pizza and anti-capitalism shenanigans. And the NYPD has come up with a weird way of cracking down—with an old law that outlaws masks at protests.

According to the Wall Street Journal, five protestors have been charged under an "obscure, 150-year-old statute that bans masked gatherings."

A lot of these people have been wearing bandannas, but it's safe to assume some were wearing the Guy Fawkes mask, the trademark of the hacktivist group Anonymous, that's helped organize the protests.(Well, actually the trademark of Time Warner, which makes a rather ironic profit off of Anonymous' masks.)

According to the WSJ, the law was enacted in 1845 in response to protests by "tenant farmer". (What? Maybe those were the hacktivists of their day?) The protestors dressed up like Indians in "calico gowns and leather masks" and went on a rampage.

Luckily the law makes an exception for masquerade parties, or else Halloween on the Lower East Side would be an absolute disaster this year.

[Image via David Shankbone/Flickr]