The DJI GEO page where you do the self-authorization request states specifically (bold added to highlight specifics):But you will have to do it 24hrs in advance of the time you want to fly...
"Unlocking an Authorization Zone is instantaneous using DJI Go when you are ready to fly within, or when your aerial system flies towards, an Authorization Zone. Unlocking lasts 24 hours and takes just a few taps on the screen. Users planning to fly in an Authorization Zone without a live connection to the internet may use this online Advanced Unlocking system to schedule a maximum of 30 simultaneous unlocked zones. Each will remain unlocked for three days.
Only Authorization Zones, yellow highlighted areas, can be unlocked. Simply click on a yellow highlighted area to unlock it. Red Areas are Restricted Zones that cannot be unlocked. Green areas are Warning Zones that do not need to be unlocked but are still subject to safety precautions. You can display or hide different areas by selecting or deselecting the appropriate checkbox."
Seems not to be so onerous as you claim.... once it's actually implemented, we shall see I suppose...