The article indicates the opposite: this is a real situation (it's explained why they are asking) and like Zach Holman states (somewhat exaggerated, true): unless your software has no users and is only one hour old, you'll find yourself in this situation.
No, the article doesn't reveal anything about where this data comes from, other than the vague "user input vs database" which is useless.
So their problem is real-world, and has a solution. We're supposed to solve the problem without the benefit of the context that they have, which makes it a contrived academic problem, which was my point.
The article indicates the opposite: this is a real situation (it's explained why they are asking) and like Zach Holman states (somewhat exaggerated, true): unless your software has no users and is only one hour old, you'll find yourself in this situation.