The problem with customer services is they are reading a letter that has been composed in hindsight, with plenty of time to polish the excuse, possibly run it through this or similar forums to remove the anomalies and maybe even find a better story, and hrow in a few comments about how rude and unhelpful the front-line staff were it usually reads very well.
The front-line staff, however, have been able to hear the unpolished excuse, see the body language, and ask questions to establish what the real story may be.
I've seen it too often to have any faith in the system - that's why I laugh out loud at threads which accuse TOC's of entrapment or underhand attempts to prosecute passengers - the system is undermined every day by the TOC's own obsession with "Image". They want staff to take money, but never upset anybody in doing so!