Feels like it's also going to be handy for selective prosecution. Say you're targeted for public speech someone doesn't like. Now they can try and draw some link between your travels and some unsolved crime. Even if it's a weak link, and they can't win in court...the bar for arrest is pretty low.

And, a bit of a reach, but it's also some of the foundation for "pre-crime" type stuff. "You've exhibited patterns of comings and goings that suggest..."