Yes, the automatic dismissal part is both problematic and foolish. But beyond that, I am a hiring manager, and I really can't tell you which people I've hired

Yes, the automatic dismissal part is both problematic and foolish. But beyond that, I am a hiring manager, and I really can't tell you which people I've hired have sent me thank you notes. I'm pretty sure it's a small minority. I have yet to hire someone who's a "bad egg" or just doesn't care about their coworkers. Beyond that, expecting people to adhere to a protocol they simply may not know is unfair. As I've said elsewhere, the original author should take the things she thinks a thank you note shows and just screen for them directly, rather than extrapolating from a norm that some people may have and others may not for reasons that have nothing to do with anything. If I thought an applicant knew they should send a thank you note but that they just dropped the ball, that would be a negative sign. But I see no reason to assume that.