"It only takes one person to pick up a smashed glass - it's good to be prepared in case the worst happens."
She said aggro was fairly rare. Officers travelled in pairs or with police and had contingency plans if anything went wrong.
"When we don't like the feel of it, we back off a bit."
The vests had the bonus of keeping the officers warm on cold nights.
"It's a little bit weird at first: they're quite heavy and restrictive. You get used to them quite quickly," she said.
Council licensing and compliance manager Carole Todd said: "We issued them just prior to the Rugby World Cup on the basis that safety is paramount for our officers. It's a sign of the times - not that any of our officers have been assaulted.
"At the end of the day we've got to take precautions."
She said officers worked the bars on game nights until as late as four the next morning.
"Our officers were quite happy to wear the vest. They're working alongside the police in an environment that can get aggressive."
Usually a team of 13 monitored compliance through the whole council area but numbers had risen to about 25 for the Cup.
They would probably keep wearing the vests after the Cup as well.
The officer in charge of the police alcohol harm reduction unit, Sergeant Bryce Law, said overall pub patrons had been good during the tournament.
"Since the first Friday night things have improved.
"The bars have been quite well-behaved."
