from the Kapiti Coast Facebook Page :-

Tonight at around 7.30 pm a friend of mine kindly went to New World Waikanae to get my shopping for me as I am recovering from knee surgery I waited in the car. I gave her $100 note and unfortunately it fell out of her back pocket. When she was frantically looking for it a young woman in the shop said an elderly lady had picked it up. They both thought she would have handed it in but NO!! If anyone hears a lady telling a story about her luck at finding it please pass on from me my disappointment at a mature woman’s dishonesty. She knew it wasn’t hers. I work very hard for my money and my poor friend feels so guilty for dropping it. Also she might like to know she was seen picking it up on their security camera .. perhaps she might like to do the right thing and return it to the shop where they have my contact details.

The simple principle is that is if you find something which is not yours then you hand it in; in this case to the store’s customer service desk.  They should take your details with a policy that if it remains unclaimed after 10 days then you get it.

It’s probably a different situation with a small denomination note found in a public place; but $100 isn’t small (except to lawyers and executives) and it wasn’t a public place, even if used by the public.