There is no way to turn off mobile data prior to boot up
For the superman or superwoman user, this isn't a problem as they enable airplane mode always prior to shutdown.
For normal users, it's different. You could be walking for a while and lose power and then need to charge your phone in a new city and don't want the phone connecting to a tower.
Yes, people like that shoukd be WiFi only and all the superman and superwomen do that already.
What about the rest of us?
I need to get into AFU mode just to change it.
I wish there was a default timer: don't connect to anything for 1 minute upon AFU.
Real complex situations, like proestors or dissendents, don't always have time for perfect OpSec.
I'm just a regular user, which is why I use my real name, Angela. After all, I have nothing to hide... But what about other users?