Having completed selection interviews with the assistance of a panel of senior and experienced personnel, there are usually some further processes required before confirming that an offer should be made to a preferred candidate.
As well as reference checks to verify that claims made by the candidate are backed up by people who worked closely with them, for some roles additional ‘integrity checks’ are required such as a Police Check and/or a Working with Children Check. Some larger organisations also use psychometric testing to screen candidates (usually before shortlisting) for integrity, honesty, personality, and perhaps also specific abilities or skills.
As the CEO of a small not-for-profit, I used a different measure for integrity checking, which was admittedly more basic and subjective, but which nonetheless proved to be quite helpful, especially where the selection panel was torn between two apparently well-qualified candidates. I made it part of my standard practice to confer with our organisation’s ‘mystery‘ panelists.
Our receptionist was an experienced and insightful person, and so I trusted her advice on the manner in which she had been treated by the candidates before and after interview. I would also check this same question with the staff member who had been nominated as the contact for candidate enquiries, who was usually the Executive Assistant.
As you might hope, there was usually good congruence between the impression the panel had gained of each candidate and the views formed by the mystery panelists. Occasionally however, I would discover that the person we held a positive view about had behaved poorly towards one of their prospective colleagues. This suggested they were well practiced at managing up, but may not be good team players. The additional insights gained by checking in with our mystery panelists helped us to more effectively manage the risk of ‘selection regret‘.

Various cultures use an expression like ‘street angel, house devil’ or ‘Jekyll and Hyde’ to describe a person who is ‘two-faced’. Such people behave well in public but may be arrogant, bullying, or in extreme cases, even violent in private.
A candidate who treats your receptionist in a rude, abrupt or dismissive manner is not one you want joining your team, as they will damage your culture rather than enhancing it. I therefore encourage you to consider including your receptionist as a mystery member of all your selection panels.