Whilst I am open to the possibility that the CCTV footage was incorrect and that a genuine charger is to blame, the possibility of such an event is almost zero with the strict guidelines and higher than required safety mechanisms. The event of the same event happening with an unofficial charger is much, much higher.
If you have an unofficial and cheap charger please buy an official or reputable charger. Cheap chargers are dangerous and can kill you.
What could Apple do? It already is trying to limit third-party Lightning cables by showing messages to the user that the cable is not genuine which "triumphantly" get circumvented by other manufacturers. If push comes to shove they could restrict charging only to authorised and genuine chargers with genuine cables to try and prevent this from happening. But that would be one step too far which nobody wants.