I don't doubt you in the least: I've also seen BS artists who got through interviews without being able to so much as write a for() loop.

But I've never seen anyone fail upwards as far as a Principal/Staff Engineer level. Last time I interviewed at that position, no one even asked anything about code. They were more concerned about my position on architectural choices, pros and cons of various approaches, knowledge of applicable standards and regulations (I'm in the medical device field), mentoring and team leadership issues and how to resolve them, etc.