Sorry, shot from the hip. BUUUTTT, in this day in age, highly unlikely you would ever get a clearance that purposely took you through a P area, even if was not "active". Unless you are mission specific and got military approval/arrangement ahead of time. I would question any clearance that was taking me through a P area and ATC didn't specifically state "this will take you through P Area 40". If you are lucky and an erroneous clearance took you through a P area, you might hear someone calling you on 121.5. If you are unlucky you may be "escorted" or worse shot at. They aren't playing these days. Check those TFRs.