Anita
I guess I am in the minority here. Before I detect in a new town or city, I call the police department (they're the ones who enforce the laws) and ask this:
"Are there any laws pertaining to metal detecting on town/city property such as parks or schools". Yes or no answer. I get the name of the person (usually an officer/dispatcher) and note it in a small notebook I carry with me. I have never been stopped or asked to leave a place. I won't ask at town/city hall - I go to the PD, that way if I AM asked to leave a public property by a police officer, I can say, "I spoke with officer XYZ and he told me there is no problem detecting here". I never, ever mention digging, holes or anything else that can be construed as damaging to the property.
This is my 2 cents...hope it helps.
HH,
Anita
Anita, your tactic has been discussed here before. Basically, it's the tactic of not going in and asking "can I metal detect in the park?". But RATHER, phrasing it carefully so-as-to put the burden of proof on them, to CITE such a law or rule (if one existed). Eg.:
"Is there anything that prohibits metal detecting?" or "
are there any rules that address metal detectors?" and so forth. And yes, you can take it a step further and ask the police dept. (which usually admittedly has BETTER things to worry about in today's crime-ridden society!), as opposed to city-hall or park's dept, which might answer differently.
And you're right, this is certainly better than asking "can I do such & such?" (as if you're asking their personal whim or opinion). And appears to put the burden of proof on them to city any rule, if one existed. That is certainly an improvement.
But with the following notations:
a) Some people have done just that, and STILL gotten odd responses, like 1) yes but you can't dig (EVEN THOUGH YOU NEVER MENTIONED "DIGGING" or "HOLES", etc..) 2) We would prefer you didn't (as if you had just asked their "opinion" or 3) "no" you can't (as if you'd just asked them permission). And in each case, if you press them and say "but where is that written?", guess who's going to win that debate?

They merely morph something else they say applies.
b) I notice that you are careful in your wording to keep any mention of "digging" or "holes", OUT of the question. Good. Because of course you and I know we will leave no trace of our presence, so ..... that fulfills the spirit of any such rules or morphing on that end, RIGHT? But even when you've gotten a "yes" to your type of phrasing, it still doesn't stop you from being there in the the field (permission or not) and having someone come up and gripe. I mean, afterall you are "digging" and you "never mentioned that in your request". Doh! Thus yes, people have proudly produced their "permission", only to have it just-as-quickly revoked in-shame, when the city-worker gets on his cell-phone, calls down to city hall, and claims ".... but he's digging the place up!"... (which of course isn't true, but do you really think you're going to win that debate?)
c) I notice you say that in all the time you've used this tactic (of careful phrasing of your question to the police), that: "
I have never been stopped or asked to leave a place". When you say you've "never been stopped", do you mean that .... you've never even been "carded"? Ie.: forced to cite your authority, their subsequent "yes" and so forth? If so, then is that assume that if you'd NEVER asked, that ....... the results would have been the same? In other words, if no one ever came up to attempt to stop you, then, the outcome is exactly the same it seems, since the "yes" or whatever never came into play?