Alot of the time if you call to ask if its ok even at a city park if the person you talk to doesn't know if it is or isn't ok they will tell you no I guess to error on the safe side so it doesn't come back on them telling you it was ok when it isn't, then to find out its fine to hunt there. Most county and city parks around here its fine to detect and there are no laws against it. I have a few private places to detect I didn't get to last year because of it being so dry and its nice yards I didn't want to hunt because it was so dry you couldn't even keep a plug together the dirt would crumble and the grass would just fall apart not to mention it was like concrete. I even had one guy say he didn't care about the yard but I told him I do, he might have cared if the lawn mower started throwing grass chunks out, I told him I'll talk to you in the spring. If I get all my private places done I'll check in to that state park to see if they will give a permit but I doubt it.