Hm, I don't dig this. I don't think it's ethical to evaluate a candidate's interactions when they weren't informed they were being evaluated. People are stressed heading into an interview, and may be upset afterwards. Unless they're interviewing for a public-facing role, I don't see how this behavior is relevant to the job; and discussing it with a hiring committee invites all sorts of "cultural fit" biases that make the hiring process inconsistent and discriminatory. If a person's behavior would hinder their ability to do the job, then that's worth a rejection; but "rudeness" is a very subjective thing.
edit: to clarify, I'm talking about behavior that could be interpreted in different ways by different people. If you tell a driver to fuck off, yeah; I don't want to hire you or work with you. The parent gave no example of the behavior they'd reject a candidate for, and I assume it'd be reasonable; my point is just that this kind of thing is hard to do right and I'd avoid it.
edit: to clarify, I'm talking about behavior that could be interpreted in different ways by different people. If you tell a driver to fuck off, yeah; I don't want to hire you or work with you. The parent gave no example of the behavior they'd reject a candidate for, and I assume it'd be reasonable; my point is just that this kind of thing is hard to do right and I'd avoid it.