That is part of it. But on the PnR, two things either happens. Dalembert or Paterson stays on Parker and no one switches onto the big. To make it worse they don't step out to the 3 pt line to do this. They do it at the free throw line. You either step out and trap forcing a bad pass or you show quickly and get back to your man. Parker is met by the big man near the paint, and the help side defense does not get over to help on the now open big man.