It works for (the US) military because they assign unique NET codes to groups and unique keys to transceivers. The frequency schedule is seeded using part of th

It works for (the US) military because they assign unique NET codes to groups and unique keys to transceivers. The frequency schedule is seeded using part of the key, the NET, and the day. The system is actually designed with the assumption that transceivers will fall in to enemy hands. Starlink could implement something similar where the schedule is seeded using a key stored on the device, the day, and the receivers serial number (or other unique value). Supporting a million receivers is the same as supporting one, it is basically just one more input to a hash function.