All civilian dedicated GPS units can get better than 5m accuracy now. Smart phones will do almost as well and sometimes even better when tracking on towers but I would assume that the searchers were not using a smart phone to track with. I've used cheap arduino gps units for water samplers at sea and the tracks compared to within 2m of the ship's military marine grade units. Don't government search teams have access to military grade GPS? This would probably be better than 2m accuracy under poor conditions.