I’ve always been amused how bizarre the requests are for an item or document ID.
In the Old Daze we had to use 8.3 to create a Taxonomy. We had folders as well.
So you could end up with 061982.xls in the Sales Folder. You could also end up with 061982.xls in the Finance Folder. Confusing eh?
It got a lot better later on when Microsoft completely dominated the Network File Share market. But I digress.
Users want a unique identifier to find the document, files, and items that they create. And once that identifier is assigned it better stay that way upon peril of death.
So that should be kind of easy right? How about when System Administrators take all of your data and move it to a new system? What if the unique identifier was system generated on a web page and the user could intentionally or unintentionally inject additional characters into that field defeating your Taxonomy based Algorithm?
You would end up with junky data. And once you hand that junk to the user as a unique identifier then that is their Baggage Claim Ticket. Hence the Baggage Claim Datatype.
Whatever you do with the item/ document/ file when the user shows up with their Baggage Claim you better have it ready.