Get permission in writing on Airport Stationary with their letterhead (if possible get it notarized), get a copy of the Alabama Code on trespassing, get a copy of any regulations pertaining to metal detecting, if possible get a boundary map showing property lines, get copies of Alabama Code on unlawful arrest. Carry all this with you in a folder along with your credentials.
Then go back and detect that spot, when she comes back and confronts you calmly and politely show her your paperwork. Do not leave if you have permission, if she arrests you then comply politely and calmly, even while detained at the jail. Then when you get out sue the hell outa them, either way you win, unless you don't think a night in jail is worth ten or twenty grand.
Alabama Code on Trespassing
Section 13A-7-2
Section 13A-7-3
Section 13A-7-4
Alabama Code on Habeas Corpus
Section 15-21-27
Section 15-21-31
Section 15-21-24
Section 15-21-30[/h]