Under what conditions can customs officers conduct searches at the extended border?

The correct answer emphasizes the requirement of having reasonable suspicion of criminal activity for customs officers to conduct searches at the extended border. This involves the officers forming a belief, based on specific and articulable facts, that a person may be engaged in illegal activities. This standard is crucial in the context of the Fourth Amendment, which protects against unreasonable searches and seizures, ensuring that law enforcement authorities have a legitimate reason to initiate a search rather than acting merely on a whim or arbitrary basis.

The presence of reasonable suspicion is a legal threshold that helps to balance the enforcement needs of customs officers with individuals' rights to privacy. It avoids broad, unrestricted searches and promotes more focused enforcement actions.

Other options imply conditions that do not meet the legal requirements for searches. Random inspections would not be justified as they lack a particularized basis for action, while suspecting someone of merely carrying illegal substances is insufficient without the supporting facts that constitute reasonable suspicion. Additionally, the availability of time alone does not confer authority to conduct searches, as proper legal justification is fundamental to any enforcement action.