An interview may go so well that emotions could lead the way and the temptation of making an offer in a gut reaction seems like the right call- but that is never the case. There should always be hiring procedures- and everyone should follow them to the fullest extent. If there is a survey that one employee is to fill out, all must fill it out. If three references are always required, then always require them. If a math test is required, than all must take it.
Circumventing the accepted and published rules because a manager has a gut feeling about a great candidate is always a mistake. First of all, there is legality to consider- in our litigious society, the last thing a company needs is a “potential candidate for hire” to file a claim stating that they were treated differently/unfairly and fall victim to an unintended legal suit. In addition, word tends to get out in a community that a company hires people with an inside track and that can impact how a company is perceived. Finally, employee morale is best preserved if all employees feel that there is always an underlying doctrine of fairness and all have an equal chance for advancement. Skipping rules and going with a gut feeling will only serve to undermine the important process that all have come to respect in hiring new employees. So, even if it seems like an unnecessary nuisance, follow through with the entire hiring process as specified and do not skip any part of it.