This is a fictionalized question to help me understand an element of liability I stumbled across recently. My parents are not infirm and do not live with me.
I am well past the age of majority. One of my parents has diminished mental capacity and lives with me on a large property I own. My parent does not drive and there are hazards to vehicles on the property.
I sell a large widget which requires to be picked up on the internet. Prior to arrival I advise the purchaser of the existence of hazards (say muddy ground which will cause the vehicle to get stuck) and instruct the seller to park at a location free of hazards so I can assist them in navigating the hazards and picking up the widget.
On arrival the buyer comes across my parent (who identifies themselves as being my parent). The buyer does not have reason to believe my parent is infirm. My parent then instructs them to the widget stating that they do not need to worry about the hazard.
The vehicle get stuck in the hazard, and because of its location it is expensive to get back on the road. The vehicle is not insured against this kind of loss/damage. Who is liable for the costs associated with recovering the vehicle?
FWIW, I am in New Zealand, but I'm interested in the general principles here, including those that apply to other countries.