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Won't help. It gets the information from the telco provider, and does not require GPS or any other fancy hardware.

It helps in the sense that it's difficult/impossible to browse the web on dumbphones, so they won't get your IP in the first place.

Might as well keep the iPhone and turn off mobile data and wifi.

I think a pre-paid (burner) phone would be anonymous.

Not true. If you refill using a credit card then they collect the info at that time. I use T-Mobile prepaid and they have all my info except my name.