I hate to make light of the situation but

“If you omit you’ll get to quit

Sounds to me like the individual in question tried and failed to keep this under the radar.
A letter in your file is a letter in your file no matter how trivial as that wasn’t the question.

It’s like a suspension of your certificate by the FAA, doesn’t matter if it was for a single day or for 90 days.

“Has your certificate ever been suspended?”

-Yes

It’s got nothing to do with fairness though.
But a lie is a lie even if it’s by omission.
Present employer I was asked during a break in Indoc to have a brief chat with Head of Security.
Something needed clarification.
I’m 100% sure he already knew the answers to the couple of questions he asked about my background.

And ‘the day before Thanksgiving’ part?
That’s a little over the top.