Trust no manager
Gidday Robert. The plastic beaker you’re referring to is a foam holder that insulates the bottle and keeps it cold. It stops the heat of the hand, and the heat of the Australian climate from warming the beer. Australia is a very hot country, and New Zealand is pretty warm, too. It’s probably because of the climate that beer is traditionally drunk cold, and that’s preferably ice cold, both in Australia and New Zealand, not warm as it’s traditionally drunk in the United Kingdom. Most Aussies (Australians) and Kiwis (New Zealanders) find drinking warm beer about as appealing as drinking boiled cola!