If you are parked at a remote stand in Langkawi, how can you possibly know as a pilot wether your passengers are coached/walked to the correct entry? I don't know Langkawi operationally, but looking at my own destinations, sometimes it is clear that my passengers are going through a domestic arrival gate, but other times I would not have a clue. That responsibility is delegated to the handler. Same as I don't personally count the bags in the cargo holds...
I do take your point on board that during a diversion one might have to double check wether pax have been through immigration already. Having said that, I still don't see the big deal. These things happen. It's not newsworthy.