At this summer's HOPE conference, Joshua Aaron spoke about ICEBlock, his iPhone app that allows users to anonymously report ICE sightings within a 5 mile radius, and to get notifications when others report ICE sightings near them. You can see the full talk, and the lively/infuriating Q&A, here,
Getting the information in the first place is a targeted search. Unless Apple goes full collaborator they will require a court order. They have already made the decision (for whatever reason) to target you.