I prefer pushing the constraints to motivate a different solution instead of asking them to do an unmotivated exercise.

“Google Sheets is a great solution for two people, but let’s say the department expands and now it’s ten people. How does this change your answer?”

It’s easy to break Google Sheets as a workflow by increasing the number of users, adding complex business logic, etc.

It’s interesting to see what candidates come up with and how they think. Sometimes the solutions are genuinely interesting. Mostly they’re not, which is okay. If you don’t give yourself the opportunity to learn as an interviewer, you’re missing out.