I don’t think they will mail them from NY with the official envelopes showing. They could fill them out in NY, mail them in an innocent looking box (or boxes if they have a lot), then mail them inside GA or stuff them in a drop box.
This is exactly what is happening for the runoff. The Dems feel they need to take the Senate at all costs or else it is non stop investigations and hearings until 2022 on the voter fraud, Biden’s son, Covid overreaction, tech company duplicity, ect. If Schumer controls the Senate no investigations and no hearings will take place.