I think you have to look at a couple things with that comment. For one, most of the time when a valid person contacts you for help, they're normally already at a point where they're not considering such things. And probably not thinking clearly either.
It's part of our job as investigators, to stay rational and help them with desicions such as that. Giving them the options, and the possible pluses and minuses. Then it would also be a good idea to draft up a short contract for their and your (as an investigator) protection which simply outlines things such as accidents, disclaimers, and damage waivers.
Be prepared to clearly explain the reason for each of the items on the contract.