I've offered to and it was agreed to share the finds. Then said "all personal type item" should stay with the property/owner and that I was a coin guy and would like to keep the coins. He was good with that. The farm had been in his family for over 100 years and I used to share cut firewood for his dad many years ago so we sort of new each other anyways which helped. This was done before I even had a detector on site. Worked well. Found a dogtag that was probably his great grandfather's dog from 1920 a few buttons and some 1800's flatware went to the owner. Only coin I found was a 58' flying eagle but was still a happy camper with that. But somewhat depressing as research prior showed since 1830 two families of 15 persons had lived there. Massive filling around the farmhouse since the 1940's. But getting back to the OP issue, just walk away. Looks like they were really looking for a free archeological service for their property or they saw that opportunity when you asked for the permission. Not that uncommon.
sounds right! happens! gotta remember!..it's their land! if they want to be 'cute" like that, not much you can do, except walk away.another reason why, it's a giant pain in da ass asking' permission! ..just sayin'
(h.h!)
j.t.