I guess that all depends upon the park. I live in a smallish city with quite a few parks. Many of them date back to the middle 1800's. "A couple bucks in clad" is not what I'm (by a long stretch) looking for when I go there. I have tremendous respect for my fellow man and my fellow citizens. I go out of my way to be accommodating to the overwhelming majority of them. There is a park a block from my house that is about 12 acres. They just put in one of those disc (Frisbee) golf courses on it. They used some of my money cutting 150 year old oaks, pouring concrete "tee boxes", buying the things that simulate greens and putting up signs at each hole showing the layout. This feature is predominately for adults to use but also children. It is also a dedicated feature that is likely to see little use that was put there to entice people to USE THE PARK . Now, if at 7am Saturday I only have two hours to hunt and want to go to that park, instead of wasting 45 minutes round trip driving somewhere, am willing keep to myself, not get in anyone's way, treat the property with respect and leave it just as good, if not better than I found it, what exactly is wrong with that? Now what if I'm also willing to hike down to the tot lot and take my $2,000 detector and sweep the kiddie area, when no kids are there, with the primary purpose being to make sure there is nothing that is dangerous to the kids such as some heroine addicts needle, or make sure that at last nights crack house/ coven love in some whack job didn't scatter razor blades since my last visit because the ghost of Aleister Crowely told him it would be funny, does that still make park hunters beneath the "private property" elite's? My household income is a quarter million dollars a year. Those three bottles in my avatar are worth about $10,000 and that's a very small portion of my collection. If you see me in a park rest assured I'm NOT looking for clad. I do this for the enjoyment of digging up items that were lost decades or centuries ago. Some of you need to quit stereotyping those who you see hunting in a park and you need to quit looking down your noses at them. (This is not directed at you personally Harvey). Just needed to add some more perspective to this conversation.
I have to say this about the coach or ANY other coach that would have done this to me. I have been trained to deal with these things and yes approaching someone you don't know in an intimidating manner is NOT a good idea. My jacket would have calmly came off as I started to shoot the sh** a lil the whole time setting him up.......I would have then got sh**y right back if he was and tried to initiate a swing at me. I love my jacket! Great for wrapping up a weapon and opponent in order to beat the snot out of em! 
deeper and deeper.
Hey, if you can't dazzle 'em with brilliance, baffle 'em with BS.
Geez!! Can we give this a friggin rest!! The OP has not been back to this thread. Nobody who has posted was there except the OP and the coach person. Winter is over, (in most places) you all should be out detecting instead this continued back and forth!! 
