How should employers treat the problem of employees not coming in to work on the day following a work-related social event?

Employers should consider warning staff beforehand that unauthorised absence the day after the event may be treated as a disciplinary issue. But they should remember that employees are likely to phone in sick rather than simply failing to come in to work. While an employer might have strong suspicions that a hangover is the real reason for the absence, evidence - not merely suspicion - that the employee is not genuinely sick is what is required.