Hi Dean, if you are growing the plants yourself and using the leaves in your own way (simply for flavour and spice in cooking), then it is a simpler matter (essentially confined to you grabbing a few leaves within your private garden). If you are collecting leaves from plants that you haven't cultivated (growing in the wild) and/or you are using them in a way that is consistent with established rongoa (medicinal), then that potentially invites comment. The easiest solution would be to grow some of your own plants (you can buy them from a number of nurseries), which will undoubtedly thrive.