glad you got permission.
..... and digging on property ....
This was a predictable, and understandable, response.
I have found it odd when someone posts how they were "hiking through the woods" (or some such type out-&-about story) on their daily walk, and chanced upon some cellar hole, or rock foundation, etc... They take a picture, and lament: "
Wouldn't it be grand to be able to detect here? If only I could find out how or who to contact.
Afterall, I don't want to trespass". And then I find it odd, that ....... on the one hand, they were STANDING RIGHT THERE looking at it, taking the picture, and so forth. Thus .... doh .... obviously access and simply to "be there" is not the issue
So when you point that out to them, they did as you did: They differentiate metal detecting, with simply being there, or taking a pix, etc... That's an understandable (albeit not legally defensible one, by the way, if someone wanted to say you're "tresspassing", it really wouldn't matter whether you're just standing their, or standing there with a detector, DOH!

)
Here's my answer to this: The intrinsic implication of the statement about "digging" (which you make), inherently has what connotation or mental image? HOLES of course. I mean, what else can the implication of the word "digging" be after all? That's the knee-jerk impression anyone has, when the word "digging" is bandied about. And yes, I would agree, if you're leaving holes on a site, and physically damaging a site or the ground or a structure, then sure, that is different than (although not legally) simply standing there, or walking your dog, etc... In my mind, as long as I leave no "holes" or any trace, then I have satisfied this dilema (assuming, as I say, that simply the act of being there, is not the issue). Now, sure, someone can still gripe. But so too could someone have griped when/if you're standing their looking in the windows.