I can't say that I really agree with this.

This definitely doesn't hold true when applying for a smaller startup, because odds are the person interviewing you is one of the core developers. Depending on the size of the startup, it could be the only current developer!

When applying to larger companies, world-wide corporations, the interviews aren't usually done by a single person, either. It's not like you go in and speak to their HR person and then that person takes notes on your reactions to questions. All of the interviews I did in these scenarios were multi-day, multi-interviewer interviews. I would speak to developers, and project leaders - all of which knew their stuff.

I've done both kinds of interviews, and I don't think BSing your way through any of them would have worked.