The Traveller's Aid Society travel zone
classification for a nation, world, or system which is dangerous to travellers. In general,
the imposition of a red zone classification indicates the location is quarantined,
interdicted by higher authority, or at
war. Red indicates entry into that location
is prohibited or strongly advised against. It is more severe than an
Amber Zone, which merely advises caution.
Quarantine indicates that a dangerous disease is present, and the danger
of war is self-explanatory, but interdiction requires further discussion.
Interstellar governments often find it necessary to restrict access to worlds
or systems for political or military reasons, and they do so by publishing
Enforcement of interdiction varies with the reason for the restriction. Interdiction
may be imposed on a world if it is a military base or other sensitive installation,
for the private reservations belonging to powerful families desiring seclusion,
for developing societies which the government has elected to allow to evolve
in isolation, or for valuable resource areas being saved for later development