computer-based profiling and analysis, detector dogs, Smartgate, container X-ray facilities, closed-circuit television (CCTV) monitoring and other means. Customs officers at air and sea ports, in addition to performing basic immigration control (see below), assessed passengers arrival and departure cards, and had the authority to scan and search passenger baggage. Quarantine risk material could be referred to Australian Quarantine and Inspection Service officers. Goods arriving from overseas by post were cleared by Customs and AQIS officers before being released to Australia Post for delivery. Customs collected goods and services tax (GST) on taxable goods imported into Australia. Customs administered the Tourist Refund Scheme (TRS) for tourists visiting Australia temporarily or Australian residents leaving the country, allowing them, under certain conditions, to claim a refund of the GST or Wine equalisation tax on items purchased in Australia. People smuggling The Service was the lead agency in the Australian government's response to people-smuggling and often performed activities on behalf of other agencies including: Monitoring Australian waters for potential people smuggling vessels Intercepting boats carrying immigrants without valid visas with Bay Class vessels Transporting people found in vessels to Australian territory for immigration and quarantine assessment Coordinating education and awareness campaigns overseas to deter people-smuggling activities Terrorism The Service operated under the 'National Counter-Terrorism Plan', which was a plan intended to mitigate any risk of terrorism in Australia. The Service worked in conjunction with other Australian Government departments to screen and target any potential threats moving across the border, including: Air and sea passengers Cargo (sea, air and mail) Maritime surveillance Remote area patrols Illegal entry The Service was responsible for processing all travellers entering and leaving the country. At the border, Service officers would check all passengers to ensure compliance with customs, immigration and quarantine requirements. The Service's purpose was to stop people without correct documentation or visas from entering the country. Controlled substances One of the largest areas of work undertaken by the Service was in relation to the importation of narcotics and precursor substances and the smuggling of illegal amounts of tobacco. Examination techniques such as x-ray, trace detection technology and detector dogs were used to screen people, goods, mail, vessels and aircraft moving across Australia's border. Prohibited material Australian law prohibits the importing of any material of an offensive, grotesque or otherwise objectionable nature. The Service worked to prevent the importation of material that was either refused classification by the