No I think it's an actual term they have in the tourism industry. It's "colloquialism" in Queen's English but in Redneck, that's probably how you say it lol.
Then it sounds like Shoulder Season is your kind of time to go too! I plan my trips around May/June or September to avoid the rush. I remember when I was heading back to the city I felt suffocated just for that short instant but the population of NZ is only 4.5 million or so. When you think London has nearly double that...!