That means anyone misusing them or copies of them couldn't be prosecuted.
Did the information become less sensitive when he took it out of the secure areas?
Were the documents re-classified when he brought them back into the office the next day?
I'll add another couple of questions to your list:
After 4 years of "insiders" and media people telling us President Trump never read anything how dumb do they think we are to believe he would take a bunch of classified documents to Mar-a-Lago?
Does anybody think President Trump personally packed up the 15 boxes and carried them out to a UHaul moving truck? Or is it more likely that some other government employees were in charge of packing up the documents and shipping them to Florida?