dirty-digger-dude, you say:
""
told me if he saw me metal detecting again he would arrest me"
I'll feel pretty stupid asking to quote the ordinance in back of a police car. "
You have a point there. Because let's face it: Some people (perhaps you) DON'T like to "
fight" things. They'd just as soon NOT have to have debates of merits with cops, city people, etc... for certain things that, to them, aren't worth the fight, no matter how "right" you may actually be.
So on this point, it's a matter of how much you want to hunt. How addicted you are to this, what your tolerance level is to confrontation, etc.... And all those criterias are different, for different people. You know, for example, how some people will cower in fear + break down and cry, if a cop pulls them over for a tail-light infraction, right? While others have a tough "don't care" attitude, and will just laugh it off. Because each of us is different, and looks at "authority" in different lights, and guages what we want to fight, based on the importance we imbue on whatever activity it is, that we wanted to do.
So with this said: you're
not going to find any public place, with giant neon signs saying "
metal detecting welcome here" + "
go ahead and dig holes, steal our cultural heritage", etc.... It just aint gonna happen. To the contrary: there are going to be people who don't like it, for a variety of reasons. And if this
bothers a person, then maybe they've chosen the wrong hobby

Sort of like driving: occasionally you will get flipped off by other drivers in traffic. And if that's a very horrible experience, then your choice is, to not drive.
Personally, I too don't like getting booted, especially when there's no actual rules about it). But I have a pretty tough skin about it. My solution, is to be much more discreet, and simply "not be seen", to begin with. It's actually gotten to where I do a lot of my park and school hunting at night. So peaceful, so serene, no one around to gripe, etc.... Kind of like nose-picking: as long as your discreet, no one will notice. But the minute you start looking for sanctions, and people's approval for nose-picking, it just aint gonna happen.