A couple of weeks ago, a nearby house burnt down. The fire was started by a battery. The house was ‘gone’ by the time the brigade arrived, in an impressive 10 minutes. But, nobody was trapped inside the house, and everyone could stand on the street and watch (or run away as appropriate). Sadly neither of those options exist for an aircraft in flight. I think it’s fair to say that the airlines would like there to be zero batteries carried, of any size or use. As that ship has sailed, they’re stuck with constantly trying to tweak to rules to find something both safe(ish) and workable. When we eventually have a complete loss of aircraft and passengers, it will be taken out of their hands, with overarching laws that have no need to be passenger friendly. Nor, as we have also seen before, are they likely to be all that effective. But, if they inconvenience everyone, then they must be good.