Regarding thinking you can simply ask the owner "has anyone ever detected here?" or asking persons nearby "have you ever seen anyone detect here?" or heck, even asking local md'rs in that area "has anyone ever hit such & such spot?": Here's a humorous story, to illustrate how answers you might get for this, can actually mean very little:
When I got my first metal detector, as a pimple faced Jr. High kid in the mid 1970s, one of the places I used to detect, was an elementary school yard blt. in the 1920s. On one such day, with my Whites 66TR (circa late '60s/early '70s all-metal TR technology), I saw an elderly man watching me from the porch of his house, across the street. So I walked over, and asked if I could hunt his yard. He said ok, so I went at it. I recall finding a few pennies, and maybe a wheat penny or two.
Years later (probably about 1980 by now), I had the latest greatest new-fangled TR discriminator (Garret Groundhog). Wohooo! I wanted to try it out in places I knew I had thoroughly combed with my older machine, so that I could compare and see how much better this new one was. Remembering that particular yard that I'd hit a few years earlier, I went and knocked on the door. This time, an elderly lady answered the door (apparently the wife of the man who'd let me md there a few years earlier). She said "Go ahead, No one's ever md'd this yard before". I guess the man didn't have any reason to tell his wife years earlier that some little kid had waltzed by on a certain day, or perhaps the lady didn't register it, or ....who knows? (What did I care?

) On that attempt, I got a few more wheaties and perhaps a silver or two from this little postage stamp sized yard.
Years later, 1983 or '84-ish, I had the the greatest new-fangled technology: my first motion discriminator. Wohoo! I figured I'd try it at places where I'd previously worked, to test its ability in placed I figured I'd worked out. So again, I remembered this yard, and again, went and knocked on the door. This time, a middle-aged couple answered the door. They said ..... well, this isn't our house, we're just home-sitting it for my parents, whom we've put in a retirement/convelescent home, but I'm sure they wouldn't mind, so go ahead". As I turned to walk away to hunt, the lady added "and you might do good, since no one's ever detected this before". Doh! You see how people assume, that if something's gone on at a family owned house (your parents house, yours & your wife's house, etc....) that "certainly I would know about it, since they would have told me". On that attempt at the yard, I got only a single deep tax token, and a buffalo. All the shallower signals were gone.
Anyhow, flash forward to the early 2000's, I know had the latest greatest Minelab explorer. Wohooo! Again, thinking of places I could try my new toy, to pit against my older machines ....... you guessed it, I decided to try this tiny little yard .... again! I knock on the door. This time, a young couple answers the door, apparently having bought the house from the previous owners some years earlier. They say "go ahead. No one's ever hunted it before" Doh!
I've seen this phenomenom over and over again in my ~35 yrs. of this. Some newbie, for example, comes into our club meeting totally confused because he just got permission to hunt a "virgin" stage stop he researched out. And yet, he got skunked. And he just can't understand, because "the farmer who let me go to the spot on the back-40 of his ranch, told me no one's ever hunted it before". Doh! I have to chuckle, because I know that it myself and my buddies who, perhaps, worked the snot out of it a decade or two ago. We got on via a guy who had the gate key d/t he had hunting rights, and that was the entrance he had access too.
There are numerous other scenarios of how this type thing happens. These are just micro-examples. And in each case, notice: the persons telling you "it's never been hunted before" will be quite adament about this. :P