[lehmannro]

Assume that the caller or user is an idiot

I think this is not helpful at all, probably harmful. There might be use cases for my code I did not even think about and third-party programmers should well be able to use it as they wish. And if they feel like modifying internal state (which the author deems fragile in his article) -- oh well! We are all adults here.

NB. I agree that the library he's examining is sub-par quality and is well worth a look.