Chipotle was catching flak for shrinking portion sizes after a video taken by a customer made the rounds on social media. Shortly after this, supposedly, they sent out a memo to managers to tell front-line staff to serve big portions to customers who were filming the process.
Then a bunch of people caught on and publicized the protocol. Since it was so obvious, it was easy to “hack”.
According to Forbes this was all a sham, but it’s an interesting case study even if hypothetical.