You are writing a client for an API, to be deployed at scale. The API returns objects of type A or B, but occasionally returns something else - not as an error, it's just what happens to be in the server's database. You'd still write code and test-cases to deal with the not-A-or-B instances, right?

But this is not an API and it is a disorder so equivalent to an error. But who says you wouldn't want to handle it in either case?

>You'd still write code and test-cases to deal with the not-A-or-B instances, right?

I've seen this one before. It was called the something something solution and was very popular in Germany a while back.

Better discription (roughly) of the purely physical case.

ie. Not binary - and can't be accurately represented as such on medical forms and other places with things matter.

You might also say these cases are much more frequent than gold in the crust.