A fair bit of the side-quests I've started in Batman: Arkham City are given by political prisoners usually by themselves on some roof. However, some thugs also like to sit by themselves on a roof, so more than once I've just walked up to them like they're someone nice then had to beat them down.
The run-of-the-mill inmate shows up as blue on Detective Vision, just like the political prisoners, so I don't see any easy way to tell them apart. Their posture seems to vary as well, but both can slouch, etc.
Is this not really a problem as you continue on (they're so rare)? Or rather, should I just assume everyone's bad and sneak up on them like a real Batman?