"It's irresponsible anyway ... you can't just not show up because you want a holiday."
It was a particularly risky move in the age of social media, which had caught out wagging workers in the past.
Campbell was not anticipating a great influx of sick days on Monday, however, there would inevitably be a few.
Some smaller companies were closing on Monday anyway to give their staff a break - sometimes because the boss wanted one, too.
National secretary of the country's largest union E tū Bill Newson said employers must be mindful that of the country's 2.5 million or so workers there would inevitably be some who were genuinely sick on Monday, February 5.
Of these, some may not need to go to the doctor and providing a medical certificate for a single day's sick leave was not necessarily a requirement at all workplaces.
"I would say it's an excellent opportunity for employers to get in front of the issue and plan around having the possibility of having that day off anyway. A lot of companies do have issues around managing their leave balance so we would encourage employers to make a virtue out of necessity," Newson said.
"Maybe not everybody can have the day off, but perhaps they could give people the opportunity to have a break and take it off their leave bill."
The allegation that large numbers of New Zealanders falsely claimed to be sick on such days was not supported by any evidence the union had seen.
"We haven't noticed any trend whatsoever in relation to these sorts of situations where there's one work day before a public holiday, and we're a large union so if there was such a widespread phenomenon we would pick that up."