You have two questions.
One, can I tect there? Yes, you can. Just watch out for the signs that say "NO FRIGGIN METAL TECTIN' ALLOWED, AND THIS MEANS YOU!." And if the signs in fact do say no tectin allowed, DONT GO TECTIN THERE!!!!!!. Dont be tempted to go there at night and try your luck. Believe me, a man of your stature does not need the publicity of a metal detecting arrest, that would be brutally embarrasing.
Second question, Do I need permission?. No, you dont, unless the sign says "NO FRIGGIN METAL TECTIN' ALLOWED, AND THIS MEANS YOU." And then you dont need permission obviously. Quit worrying about "permission" and please stop emailing local officials about metal detecting, they are too busy for such nonsense and they will just say NO!to you to get you off their backs, just like I would. Are you afraid of the police man? No cop is gonna cuff an old timer like you for swingin a tecter in Sordid Park in your little hamlet, heck, you probably know him anyway. If it's illegal, well you will get a warning and learn a hard lesson. You have to remember nobody from tnet is from your town, so we cant possibly help you on this conundrum, one way or the other. And remember, always get permission to hunt private land and cover your holes carefully and dont leave any trash laying around.