Things you'd like to tell trampers from overseas

I'm following the forum for quite a while now. I'm about to set up a small business in Germany advising people on non-guided tramping in a few selected countries/regions including NZ. I'm trying to follow an integrated approach as much as possible so that my clients are fully prepared for what to expect when they go tramping. I'm interested to know from you: What are the most important things you would like to tell visitors from overseas who come to New Zealand for tramping? It can be in regard to safety, track etiquette and behaviour, experiences you have made or situations you have been in with international trampers or whatever you find important I should also let my clients know. I appreciate your feedback, thanks, Happy Easter Daniel PS: I know the articles about the basics, I am interested about your opinion.