6-2 discussion: account receivables, accounts payables, and risk
I have found the Management Discussion and Analysis of Amazon Inc. Form 10-K which can be accessed here: https://s1.q4cdn.com/459955560/files/doc_financials/2019/annual_reports/amzn-20191231x10k.pdf
Amazon lists several risks that could lead to an overstatement of receivables and understatement of payables. These include potential losses from fraud, errors in sales estimates, changes in foreign currency exchange rates, possible losses due to improper activities, loss due to incorrect sales estimates, tax obligations new regulations, shrinkage inventory, theft, or any other irregularities which may cause inaccuracies when financial statements reporting is done.
An auditor may design tests based on the identified risks. This might include an analysis of receivables versus historical trends, bench marking against industry standard standards and assessing internal controls for foreign currency transactions. A separate test will verify that transaction pricing accuracy is accurate. Analyzing inventory levels at different locations to find any unanticipated discrepancies. Surprise audits of various warehouses could also be performed in order to detect theft or fraud.