Wouldn a voluntary NIDS improve security while preserving civil liberties?
This would be even worse than a mandatory system. First, it would make untrustworthy anyone who does not have a card. A lot of energy would be wasted checking people who are only suspects because they don’t have a card. Second, less time would be spent checking people who have a card because they apparently have already been cleared. In effect, it would make life easier for terrorists like whose who committed the attacks on September 11 because they could use their ID cards while security personnel would concentrate on those without one. This structural inefficiency of a voluntary system would create great pressure to make it mandatory over time.
