I've had a people over the years stare out of curiosity and have generally been inquisitive and polite. I just usually nod or give a quick wave to let them know that I know they are there and go on about my business.
I did have one nosy neighboring landowner approach after watching me for some time on the other side of the fence. This person clearly had seen me unlock the property gate with a key given to me by the landowner but I guess that wasn't good enough in her mind to accept that I had permission to be there. Lady wandered closer to within earshot and and said " I don't believe I know you" with what I considered a rude inflection in her voice. I could see where this was headed so I replied with "no ma'am you don't but the land owners do. Something I can help you with?". She turned around and stomped off and I later learned she's the local busy body and they meant to mention I may encounter her. No harm no foul.
Well, I was metal detecting on Sands Beach in Key West back in 1983, when a drop dead beautiful but quite drunk lady in her 30's walked up and asked "Do you ever find anything with that thing?" Now understand that back then, I was pretty buff, had a nice tan and was wearing cut-off jeans and a t-shirt with no arms. To her question, I stated "Well, yes It found you didn't it!!??" and she nearly jumped my bones right there on the beach. After getting up close and personal with drink in her' hand, she thought a minute and said excuse me, I am drunk and need to go back to my hotel room. Needless to say, I had to leave shortly after that to go home and take a cold shower.
Except for children, people in general don't come close enough to me to bother me. In parks if their parents let them I usually left them use the use the pin pointer and digger to dig out the finds. They're a bit rough but there isn't anything but a bit of clad so they won't hurt anything. They get bored pretty quickly and head back to playing. The only time I really had crowd was when I was using my detector to find a water shut off in a low income area of Orlando. Had people watching from the balconies lol.