You be the judge:

On Thursday, F.B.I. agents descended on a house in Jackson Heights, Queens, and spent 16 hours searching it. The most likely reason for the raid: a man who lived there had helped coordinate communications among protesters at the Group of 20 summit in Pittsburgh.

The man, Elliot Madison, 41, a social worker who has described himself as an anarchist, had been arrested in Pittsburgh on Sept. 24 and charged with hindering apprehension or prosecution, criminal use of a communication facility and possession of instruments of crime. The Pennsylvania State Police said he was found in a hotel room with computers and police scanners while using the social-networking site Twitter to spread information about police movements. He has denied wrongdoing.

[From Arrest of Queens Man Puts Focus on Texting to Rally Protesters - NYTimes.com]

...

A criminal complaint in Pennsylvania accuses him of “directing others, specifically protesters of the G-20 summit, in order to avoid apprehension after a lawful order to disperse.”

...

A search warrant executed by the F.B.I. at Mr. Madison’s house authorized agents and officers looking for violations of federal rioting laws to seize computers and phones, black masks and clothes and financial records and address books. Among the items seized, according to a list prepared by the agents, were electronic equipment, newspapers, books and gas masks. The items also included what was described as a picture of Lenin.

THe LA Times articles notes there two men arrested:

Elliot Madison, 41, and Michael Wallschlaeger, 46, both from New York, face charges of hindering prosecution, criminal use of a communication facility and possessing criminal instruments.

...

Police say they found the two men sitting in front of computers, wearing headphones and using maps and scanners. They are said to have been using Twitter to inform protesters on the ground of police movements.

The FBI raided Madison's home in New York and spent 16 hours searching it.
They found items including anarchist literature, gas masks, goggles, face masks and test tubes.

Books and newspapers? A picture of Lenin? These are relevant how? Is it suddenly illegal to own these items? Is anarchist literature officially the wrong kind of literature now?

Gas masks and goggles? Given the anti-protestor paramilitary and police units willingness to deploy tear gas against protesting citizens to keep dissent away from the political managers of global capitalism, neither of these items seems unreasonable.

The NY Post reports that the raid wasn't just conducted by FBI agents, but by an anti-terrorist unit. Does civil disobedience now qualify as terrorism?

Right now, none of the government's actions make sense. Is there more here than is being reported or is this a federal crackdown on dissident voices protesting capitalism?

Until I hear otherwise, these arrests seem entirely unreasonable to me.