My first thought too...
There is a big difference between someone worried about me and being detained for an hour. How would you like to be stopped and detained for an hour?
Imagine if a police officer came up to you as you left a store and asked "are you alright, it looked like you might be in some kind of trouble?" and then, after you said "No, I'm fine" detained you for a hour of questioning.
Personally, it seems like concerns about a traveler being a victim of a crime could be resolved much more quickly, without interfering with their rights.