I am fascinated to learn more about the apparatus that checks pedestrians leaving the US. I understand there is doubtlessly unseen stuff going on there. Do yo

I am fascinated to learn more about the apparatus that checks pedestrians leaving the US. I understand there is doubtlessly unseen stuff going on there. Do you have any materials or primary sources I can look at to understand what you're talking about? It has been my experience when crossing after scanning my passport the officer goes from jovial to shocked/unexpected (I don't look like or act someone who would have a flagged passport) which leads me to believe there is at least in many cases no advanced warning to them a flagged individual is approaching. Now I know the government must surely have these systems but I think it may be doubtful how effective they've set it up to be to stop people leaving the country if by foot. The flow of people leaving the border in general is just way lower scrutiny, in my experience living in a border state. I would be shocked if the average say non-violent felon fugitive has much trouble leaving if they're not on a flight manifest.