In reality I enter my phone passcode very infrequently because I use a fingerprint reader. I have set a long PIN since I don't want it to be brute forced. Because of the horror stories I hear of law enforcement and abuse of power, if I have a run in with a cop, turning off my phone is one of the first things I do. In a stressful situation where I am facing potential harm to my body or my family I can very easily see myself forgetting what that long, infrequently typed PIN is.