The ATC for all the good it does and it does a massive amount of good work. I say that as a preface to my opinion below.
OPINION
For the most part the ATC, if given enough rope, would have the AT regulated in such a way as to make the PCT rules look nonexistent. The ATC as a group (not trying to call out anyone) treat the actual trail as something to look, but not to actually use to much. That said, I would expect the ATC to resist any "opening" of the AT for as long as possible, with recommendations of staying close the rest of 2020. So, while the ACT has no authority to regulate the trail. The question will be how much weight will the various authority’s give to the ATC’s Opinion?
This is where some of the ethical questions, will come in the near future. If the .gov “opens” the AT and the ATC say’s stay off. Then what?