tltracy, this is very strange: you have several locals (I can see from the other thread) saying it's ok, have a blast, and that they go all the time no problems. Right? Yet someone's come up and told your husband otherwise? Who was he? What entity/beach was your husband on? (as perhaps there's boundries where the beach beyond a certain point is administered by another entity).
Or what might have happened is this: perhaps it's the exact same beach and entity that the other posters have told you "no problem". But that at some time in the recent past, whomever that one lone individual (was he even an LEO ?) was approached by someone asking "can I metal detect?". And then whomever that was looks long and hard through his books, calls his superiors in state capitol, consults an archie, and comes back with an answer to the "pressing question" : no. Then guess what happens when that same person sees another md'r on the beach (like your husband whom he'd probably not ever have noticed or glanced twice at): He'll remember the earlier inquiry and start booting others!
Perhaps those who've told you "it's ok", can chime in to clear this up, since apparently they have no issues. Hopefully it's not going to turn into a giant case of the: "no one cared, till someone asked" routine.