I think think this varies very much between different "cultures", such as different countries and different fields.
I make a structural engineering program which is used by pretty senior engineering types in Scandinavia and Germany, who can certainly be trusted to know that with some nonsense input, the output may also be nonsense.
The requirements for the UK are completely different - they want the program to be used not as a tool (like a fancy calculator) but as a simple black box that a novice engineer or even a non-engineer can use.
I make a structural engineering program which is used by pretty senior engineering types in Scandinavia and Germany, who can certainly be trusted to know that with some nonsense input, the output may also be nonsense.
The requirements for the UK are completely different - they want the program to be used not as a tool (like a fancy calculator) but as a simple black box that a novice engineer or even a non-engineer can use.