Influencing hiring managers is as important as influencing candidates. If hiring managers won't take your advice you shouldn't be a recruiter. The interviewing and assessment process is not a perfect science. So recruiters need to guide managers along, insuring that the best available candidate gets hired. You can't afford to spend your time showing hiring managers an endless stream of candidates until the perfect one magically appears. Or, until they're so worn down they can't tell the difference.