Idea for dig spot permission

I was thinking about how to go about finding places to dig without having to ask for permission. So I was talking to a buddy of mine and this is what we came up with. People lose things of value all the time. A lot of time they know about where they lost it but still can't find it. So I was thinking about posting an ad on craigslist offering a service to try and find their item. If they know the round about location of the item it should be fairly easy. No reward or payment needed other than permission to hunt the rest of the property. I know if i lost something of value and someone found it for me I wouldn't hesitate to give permission to detect the rest of the property. My brother did bring up a good point. A lot of people wont ask someone to find it because it is a valuable item. How would they know they can trust the person to return it. But I feel that if you have good references, it may ease their minds a bit. Also doing a service like that for people would help you build references. It wouldn't only have to be to find something valuable. Could put on the ad that willing to detect the property and share findings with the owner. Some people may just be curious as to whats on their property.

What do you all think of the idea? Bring people to you instead of having to go out and find someone willing to give permission.