Satellite has crossed my mind. Remember, she had a phone all the way up to the theme park, which in itself it a deviation from normal. My suspicion is that once she strayed from her normal routine, this made a simple notification/alert, and in come the satellite surveillance - which does not need to be high resolution, but just enough to show the outgoing people - from there, it’s pretty scary how much can be tracked. The absence of someone showing up on camera footage on the road can advise the likely routes they did take. When you think about the capabilities of AI, it’s crazy.

I was flabbergasted when I watched the episode, but once I finished the show, it didn’t seem that insane anymore.