Re: Best laid plans
It may be as simple as no one informing the developers and the tester of the "recommended" way to pass orders in specific cases.
So it was never included in the unit tests and validation procedures.
Like the time some 30 years ago when I asked a colleague working with the Sealink (ferry across the Channel) how the billing system was handling the case of a user saying "Egg" (as in Easter Egg) at the counter when buying tickets for the Easter week-end.
Of course he was a little surprised by my question, and then I provided him with a copy of an advertisement published the day before (Thursday before Easter), informing potential customers that when saying "Egg" at the counter they would get a rebate.
My colleague immediately phoned his counterpart at Sealink to get more information, and discovered that nobody there was aware of this marketing coup...
I don't remember what was done, but remember it was Friday morning, with the rebate going live on the evening, and no Internet then to deliver any needed patch...