NPR reported this morning that surveillance cameras in DC threaten to dissuade protesters from assembling and exercising their free speech rights--people don't want to be recorded, particularly if there is no guarantee that the images will be discarded within a specified, short period of time.
I personally think that arguing for First Amendment violations in this case is futile. Electronic surveillance will be a standard part of modern society--and, after September 11, certainly so in the US--and the cameras are not actively preventing people from gathering. But it is reasonable to ask whether, because of their effect on people's willingness to assemble, electronic eyes effectively amount to prior restraint; and whether, given this chilling effect, the government has even a hint of a constitutional obligation to ensure that security and free speech interests are more happily balanced.