I'll stand at the end of that table with no reservations, and no worries.. If it were not a good idea, and if the safeguards were not in place to shut down the PAU in the event of a fire, then DAL would have us remain in the cockpit until ground power was applied and the APU shut down. This is not the military where we had to post a fire guard until the airplane was completely dead. Boeing and EADS or whoever designed these systems, did so with just such things in mind... walking away from it, and if it burns, it will shut down. I sleep well knowing this. This being said, I do wait maybe a few more minutes than I uesd to in order to give the rampers time to attach ground power/air, but in the interest of fuel savings, and not worries about the APU burning down.