I have seen some questions like - Build a “travel product” for Facebook. Based on the framework, we should ask clarifying questions like what do you mean by “travel product”. Travel product could be for deciding and making travel reservation, something used when traveling, or after travel blogging and sharing product. I could propose users, user needs, solutions for each stage of traveling. What if the interviewer says - “Up to you”. What is the recommendation on how to proceed? Should I keep the scope wide and talk about user needs and solutions for each stage of travel? Or narrow it down early on, to limit the scope. If I limit, the question scope will become like - “find a doctor”.
Yes, you’re right: the interviewer is very likely to answer “up to you” to all those questions.
For a “travel product” question, I would likely do a scope cut during the user needs, probably by looking at the lifecycle (e.g. researching travel, booking travel, during the travel, remembering the travel) and pick a stage of the lifecycle before going deeper on those needs.
At the core, you’re trying to leave yourself enough scope for the solution phase: not too much, not too little. The exact right balance here is an art, but if you feel like the scope is overwhelming/unwieldy you can absolutely make a scope cut.
However you should know: for Facebook in particular, the questions are usually narrow enough that you don’t have to do a scope cut early on. (this is not true of Google)