Yuo can try to do the distinction between "dig" and "probe" (or "pop" or "slit", or whatever you want to call it), if you want. But let's be perfectly honest folks: That's a semantics game. What I mean is: Anyone seeing you probe, fish your fingers down there, and get shallow targets that way, can STILL say that constitutes digging. And odds are, they're not close enough to see you (whether or not dirt broke the surface, etc...) anyhow. They're merely seeing you from afar , and .... let's face it .... detecting has that connotation, whether you dug, or probed, or were simply only walking/swinging, and hadn't even dug yet !
Bottom line is: ALL cities have something like that for their park's codes/rules. Even if not using the evil word "dig", yet still in some form or fashion. Like "alter" or "deface", etc... Right? So if those things all automatically preclude you/me from detecting (and retrieving) in parks, then you might as well give it up now, and stop detecting.
The verbage like "alter" and "deface" is easy though. Because all such words inherently imply the END result, right? So if you leave no trace, then technically you have not alterED or defacED anything ! Yes someone can debate the semantics of that with you if they want. Ok then AVOID that individual and go at lower traffic times! Like if they're park workers, then I'm sure they leave at 5pm, etc.. right? You say yourself mikeraydj that this was one of your "favorite parks", right? Then is that to assume that you've detected there many times before, and never had a problem ? If so, then it appears to me that it's this one lone individual.
Yes the "dig" word is more problematic. I would still argue "dig" versus "dug" though, since the end result is what's at stake. Yes this won't win a debate of semantics. But neither will the alter verses altered! And neither will probe/pop versus dig!
Thus I hate to say it, but .... sometimes there are just lone individuals in this world that you and I need to avoid. Why swat hornet's nests? You can certainly try to go to city hall and get this "clarified" and "overturned", etc.... But sometimes the only thing THAT does, is simply make it an up and front "pressing issue" for a bunch of other people who .... quite frankly .... never cared.
The issue seems to be pretty much isolated to turf, right? (versus sandboxes, bar dirt, beaches, scrub-terrain, etc...). So it's gotten to where I do most all my turf hunting at very "off" times. So peaceful. So serene.
But as long as I like metal detecting, and so long as it has ... uh .... "connotations" that some people get bothered by, then fine: just like nose-picking, I'll be discreet enough in my timing such that they're not forced to watch me 
