We must implement as LAW that a SIM card can provide and only provide a Zero Knowledge Proof of "this SIM is valid for this cellular/data plan up to a specific date".
If they want to track us all the time, whatever, if they can't keep that data safe from the Chinese Communist Party, then they aren't competent enough to have it.
Now is a good time to remind everyone that a SIM card is a full blown computer with CPU, RAM and NV storage.
Further, your carrier can upload and execute code on your SIM card without your knowledge or the knowledge of the higher level application processor functions of your telephone.
Answer delayed by hours due to HN rate limiting.
And, hopefully your USB stack, or your phone's equivalent to SIM interface, doesn't have vulnerabilities that the small computer that is the SIM card could exploit.
Operating systems that center their efforts on protecting high risk users like Qubes dedicated a whole copy of Linux running in a Xen VM to interface with USB devices.
It'd be great if more information were available on how devices like Google's Pixel devices harden the interface for SIM cards.
How do you implement bandwidth quotas with this?