On 12 May of this year, Australian Customs officers inspected three boxes that had recently arrived from Singapore. The consignment docket indicated that the boxes contained pistons for a Subaru WRX, and were to be collected from Customs by Alan Astbury, an agent for a company in the western suburbs. By chance, one of the storemen was a car fanatic, and alerted Customs officers about the fact the boxes were "surprisingly light" for the pistons normally found in a high-performance car. Customs officers x-rayed the boxes and found the pistons contained cavities. Closer inspection revealed that each cavity contained 30g of a brown powder tightly wrapped in plastic, which tested positive as heroin. A total of 12 such packages were recovered. Subsequent chemical analysis confirmed a total weight of 360g of heroin of 50% purity. Customs officers, in conjunction with the Australian Federal Police, substituted the heroin with baking-soda and then repackaged the pistons. A message was then relayed by Customs to Astbury advising the package had cleared Customs and was ready for collection. Astbury collected the packages that afternoon and was then arrested as he attempted to leave the carpark. Discuss the potential liability of Astbury under the Criminal Code 1995 (Cth)