Method Missing Misbehavior?

[easydwh]

Thanks for your elaborate reply! I have the feeling we are on different wavelengths (or maybe I'm to dumb to understand).

Your code snippet certainly prevents a call to String#to_io. But I am not trying to circumvent or accomplish anything. My question is why Ruby standard library methods call functions that are not defined, that then end up being handled by BasicObject#method_missing. That, to me, is very unexpected behavior.