​KembaraXtra – Travel Terms: accountable documents
​ Travel providers issue blank tickets and other travel documents to themselves and/or their agents, and because these documents become valid for travel or event entry once completed, they are controlled as numbered accountable stock. Such documents must be issued in strict sequence and fully accounted for, and agents’ sales returns to IATA, ARC, or other transport providers must include voided tickets. The entry also notes that lost tickets may be charged to an agent at an average value.