Fail KFC Germany · 2022
A push notification on 9 November
What happened
On the anniversary of Kristallnacht, KFC's German app pushed: 'It's memorial day for Kristallnacht! Treat yourself with more tender cheese on your crispy chicken.' An apology followed an hour later blaming an automated system tied to a holiday calendar.
What went wrong
The automation knew the date was 'notable' and not what kind of notable. A commemorative date was treated as a promotional hook by a system with no concept of tone.
The rule
Never wire a promotional template to a raw holiday feed. Solemn dates and commercial dates arrive through the same API and mean opposite things.
Takeaway
This is the single clearest argument for a calendar that labels dates by signal rather than by 'holiday: yes'.