It's hard to distinguish between something being explicitly shady and just a bad system though.

"As a user, if I arrive on a booking page and the live API data shows our cached pricing data is stale, I expect the difference to be acknowledged."

Developer implements animation callout and an approximate, non-technical explanation

Cached pricing data continues to often be stale

I call those asshole user stories unless there is a logged story “as a user, I expect inventory prices to be accurate in real time.”

I don’t like user stories that are anti-customer and in the developer’s favor unless it’s clear that there’s a path to fairness.

The motivation to a system should be to have as current as possible pricing, not some nightly batch that shows cheaper, unavailable prices and pisses off people when the real price is actually checked.

I think it's not going to be so obvious. If you write a feature that is intended to deceive then sure, but the developer who wrote that feature was probably told "ok, if the inventory is below a certain threshold, then add this behavior". The feature itself is benign. Should a developer resign anytime they can concoct a theoretical way in which a feature they're writing could possibly be exploited?