so, simply connect the line-in to the line-out and record that line-in as easily as any other source? Thus, what that "microphone" captures is the exact same feed that would usually go to speakers/headphones.
Yep, this is the so-called "analog hole".
You missed the point entirely: someone else opts you in using your own phone without you knowing it. Think about that for a second. Ever leave your phone sitting out somewhere? "Simply not using Latitude" isn't an option if someone opts you in without knowing. Got it?
If I was concerned about people snooping around on my phone, I would set it to lock, so it requites a password if you want to fuss with it. Pretty much all phones can do that.