Records though can be messy across businesses (retailer, wholesaler, manufacturer). A simple example would be if the purchase order id could be entered in different formats like if one vendor has dashes (like [customer]-[order number]) and then that PO id is entered without dashes at another system.

If you do a simple search or table join you aren't going to get a match, and if the person who was asked to provide the records doesn't go the extra step to do the search again you suddenly have a lot of issues.