I've flown without ID twice. Once because I lost my ID, once to prove to a friend that it could be done. This fee will fail for the same reason that flying without ID works at all - the law is quite clear on it.
As far as I can tell, the TSA is one thing, while airline policy is another.
The law says it’s not required for security, but airlines might be justified in carrying out their own policies? Honestly curious.
No.
Most airlines only start asking for ID if you want to check a bag. But not for check-in.