Johnson Suppliers is a wholesaler of janitorial supplies that built its reputation on being fair to its customers. For its best customers (those who purchase a lot of merchandise from Johnson), it often modifies the terms of the sales to induce customers to continue their use of Johnson as a supplier. It does not disclose these arrangements in its financial statements or to its auditors. What is the name usually given to this practice, how might Johnson modify the terms of the sales, and how might a forensic accountant detect such arrangements?