Sorted records in the wrong order? Crashed, no. I can't think of any reason why a date problem would cause any true havoc. Please provide details of any case you know to be contrary to this assertion.
Date comparisons. Programs are filled with them. I worked for an insurance company at the time, and some common computations were calculating premium due, whether accidents occurred within coverage dates, age of a vehicle, etc. It was just a fact that not a single policy could be processed with an expiration date past the year 2000, so we couldn’t write a police effective starting January 1999 or later until the thousands of dat problems were fixed in all the programs. Do you think I was imagining the entire thing? I spent months working on it.