Apparently April is the month for harvesting the 'cash crop' out in the woop woops.
This article from the Otago Daily Times highlights possible issues for Geocachers, such as bumping into growers or being mistaken for growers by members of the public and dobbed into the Police for behaving 'suspiciously'.
http://www.odt.co.nz/news/dunedin/294843/cannabis-grower-information-sought
Be careful out there.