countless of problems in the world are underspecified in exactly this way, that is effectively what common sense reasoning is. Or what Charles Sanders Peirce called abductive reasoning, making a sensible best guess under conditions of uncertainty.
Yes, real-world problems are often underspecified but also they tend to come with much more context, and to be much more interactive. These sorts of problems are deliberately minimal and abstract meaning there's nothing for 'common sense' to work with.
