Ticket Trick
Design
Designer 1: Company employees need to communicate internally, but the communications should be protected from outside eyes. So only those who have a @company address will be able to create an account and access internal communication apps like Slack and Yammer.
Designer 2: Lots of programmers get bug reports through email. Let’s create a feature to transfer those reports to GitLab issues. The only way to do that without using a third party extension is by assigning a @GitLab email address to each repository. Any email forwarded or written to this special email, will be added to the user’s repository as an issue.
Assumptions
1. Fallacy of Locked door (free key)
The first designer assumed that no one outside of the company will have access to an @GitLab email address. It is exclusive to the outside world. But the other designer wasn’t aware of this assumption. They locked the door, but forgot to hide the key.