Nose Wheel First,
You are 100% correct in what you are saying, however may not be the case in this scenario.
What they are questioning is if the aircraft belonged to CA or BA? If it belonged to BA then its fair game, however if it was a CA aircraft with a BA pilot operating it, I think CA will be recieving a visit from CASA, because then the BA pilot wouldnt be operating under the BA AOC, and instead the CA AOC. Then the questions morno is asking are very fair questions.
That aircraft is leased out to companys to operate - and it used to belong to MPA in Maningrida. So the big question is which company was leasing this aircraft when it sadly went down?