Yeah.

Any good software developer is going to account for and even test all the weird situations they can think of ... and not the ones they cannot think of as they're not even aware of those as a possibility (if they were they would account for and test them).

Which is why you want somebody with a different mindset to independently come up with their own situations.

It's not a value judgment on the quality of the developer, it's just accounting for, at a software development process level, the fact that humans are not all knowing, not even devs ;)