Knowing the info and publishing the info is two different things. The no phone angle is with intent.
it's with intent to demonstrate why he had to resort to knocking on stranger's doors.
Walker was trying to walk the bus route to Rochester High School after he woke up late and missed his bus. His mom had taken his phone away, so he didn't have that with him to get directions. So he knocked on a stranger’s door for help -- and almost paid for it with his life.