that also depends which car u drive, they mostly stop mehran n corolla's
i dont get stopped even wid curtain on all 4 windows n jet black tint on rear 
i have punjab registration n using car in islamabad, pass through check posts daily
if they stop they just peek inside, dont even ask for papers
last time i was stopped at night time by rangers where they were checking all cars, he just checked inside the car, asked for papers, i was gonna hand him but he said if u have the reg book u can go 