Self-assessment in customs shifts declaration responsibility to importers/exporters and enables risk-based facilitation with post-clearance audits. Self-assessment places primary responsibility for correct Customs declarations on importers and exporters, with RMS-driven interdictions allowing review of assessment, physical examination, or both; incorrect declarations may be reassessed. Section 17 enables customs officers to carry out on-site post-clearance verification at importer or exporter premises, supporting a facilitation-first approach paired with post-clearance audits to detect infringements.