Free speech zones are, in the US, fenced-in areas set aside in public places for activists to exercise their right to free speech. Though the zones give protesters space to voice their opinions, critics claim that the cages in fact censor dissenters by delineating where they must be when expressing themselves. Free speech zones were widely used during Vietnam-era protests and are still used at various political events. For whom did one California airport install free speech zones in the 1990s? Discuss