that mode should be almost always on - the CBP in US can do all that fun stuff to you at any time as long as you're closer than 100 miles to any US border - including ocean. So, for example, CBP can do anything they want to anybody in San Francisco. Granted, for now they do that mostly to "brown" people - well they need to start somewhere to get us into that shiny totalitarian future and of course the start is always with the most vulnerable.