I hate to say this, but, having been into this for 30 yrs, I truly think the beginning of a LOT of bologna starts with well-intentioned persons "asking permission". As if something were inherently evil with their hobby, that they needed to ask, to begin with 
Example: in my town, our "central park" had been detected since the dawn of metal detectors, as far back as anyone could remember. No one ever said a thing to us there. In fact, it never even OCCURED to us in the 1970s/80s that you needed to ask permission, or inquire, etc... I mean, it's a PUBLIC park, isn't it?
Then one day in the mid 1980s, a new guy to town visits our detecting club meeting. Various persons, in the find-of-the-month show & tell, would say things like "found this @ Central park", etc... He raises his hand and says "I thought it was illegal to detect there?". We all turn and look at him saying "since when?" "who told you that?" Turns out he'd gone down to city hall and asked! Hmmm, now some of the club members got skittish, as if .... somehow NOW the parks were off-limits? Others shrugged their shoulders and figured it was some deskbound bureaucrat, but was obviously not an issue, so they would ignore this fellow's report.
Point is, guess what that same bureaucrat might do the next time he passes the park(s) and sees an md'r, who he previously would never have probably paid attention to? He'll remember the earlier inquiry and think "there's one of THEM". This is where the FMDAC mailers, with horror stories of isolated incidents here and there, actually cause people to think they need to inquire at each town, park, school, etc... And before you know it, rules get invented "to address these pressing issues". It's a durned if you do, and durned if you don't situation. Because NOW, once there IS rules (no matter how they started), you are, I guess, responsible to know them. Which only snowballs into more people asking, thus more red-flags and images of geeks with shovels coming to people's mind, thus more "no's" and on and on, round and round, it goes
Example: in my town, our "central park" had been detected since the dawn of metal detectors, as far back as anyone could remember. No one ever said a thing to us there. In fact, it never even OCCURED to us in the 1970s/80s that you needed to ask permission, or inquire, etc... I mean, it's a PUBLIC park, isn't it? Then one day in the mid 1980s, a new guy to town visits our detecting club meeting. Various persons, in the find-of-the-month show & tell, would say things like "found this @ Central park", etc... He raises his hand and says "I thought it was illegal to detect there?". We all turn and look at him saying "since when?" "who told you that?" Turns out he'd gone down to city hall and asked! Hmmm, now some of the club members got skittish, as if .... somehow NOW the parks were off-limits? Others shrugged their shoulders and figured it was some deskbound bureaucrat, but was obviously not an issue, so they would ignore this fellow's report.
Point is, guess what that same bureaucrat might do the next time he passes the park(s) and sees an md'r, who he previously would never have probably paid attention to? He'll remember the earlier inquiry and think "there's one of THEM". This is where the FMDAC mailers, with horror stories of isolated incidents here and there, actually cause people to think they need to inquire at each town, park, school, etc... And before you know it, rules get invented "to address these pressing issues". It's a durned if you do, and durned if you don't situation. Because NOW, once there IS rules (no matter how they started), you are, I guess, responsible to know them. Which only snowballs into more people asking, thus more red-flags and images of geeks with shovels coming to people's mind, thus more "no's" and on and on, round and round, it goes