After phones became de-coupled from street addresses (landline), the whole system changed to do everything possible to identify who has what number. It may or may not have something to do with law enforcement requests for wire taps and metadata. You have to hand all this information over, even if you bring your own phone.
That said, burner phones with cash-paid SIMs are probably (?) still a viable workaround, however tedious.
After phones became de-coupled from street addresses (landline), the whole system changed to do everything possible to identify who has what number. It may or may not have something to do with law enforcement requests for wire taps and metadata. You have to hand all this information over, even if you bring your own phone.
That said, burner phones with cash-paid SIMs are probably (?) still a viable workaround, however tedious.