Peanuts are actually a legume rather than a nut. Peanuts (especially those commercially prepared) are often contaminated by a mould called aflatoxin which is a carcinogen. "Even very tiny amounts - as little as 1/2000th of a peanut - can cause a life threatening reaction in some people." (Allergy New Zealand)
Tree nuts include cashews, almonds, walnuts, pecans, hazelnuts, brazils and pistachios. About three quarters of children allergic to nuts or peanuts react on their first exposure." (Allergy New Zealand)
In customers own words...
"Thank you for my order, it arrived in perfect condition, so I am now gorging myself on those lovely ginger nut cookies. I was going to share them, but not sure if I can." - Jackie Stevens, Bay of Islands
"I have just found one of your nut free Moritz Cookies in a vending machine. I have a peanut allergenic son so this is very heartening." - Clare Hughes, Auckland