Baggage is complex - to say the least...
and when it all goes wrong its normally one of the following or a combination which causes gridlock and one very unhappy baggage system -
The software engineers aren't up to the job, the complexities are not fully understood, many different technologies are used and all need to interface together without any problems, the system is very complex and the staff are not fully trained by fully trained I mean not only shown how to operate the system but also how to clear problems. Add to all that the security screening, bag tracking, hardware faults, poorly labeled baggage (bags with more than a single barcode), late bags, early bags, problem bags, transfer bags, airline bag messaging - it all turns into a very big mess very quickly if just one member of staff operates the system incorrectly, gridlock (where the system stops because bags are not being cleared fast enough to the baggage piers and into ULDs) can happen very quickly.
You have to know what you are doing - its not anywhere as simple as moving bags from one place to another.