Yeah, na. Whilst I've never had a holiday home in Wanaka, I have done a fair amount of skiing. I'd speculate that most of their skiing would be done at Ruapehu, and storing a complete second set of ski gear, particularly clothing, at Wanaka seems unlikely.
Even if all they took was undies and toothbrushes, it's still premeditated.
I know someone who has a holiday house at basically every holiday location in the country. Let's say they have a holiday house near Ruapehu and Sth island ski fields amongst other holiday houses I think they can afford as many sets of anything you can think of.