ian, to be fair batteries especially lithium/ion have a lot more potential to go dangerously wrong than a console.
the chances are only a handfull have failed but because it's a fairly serious safety risk (could cause serious injury/damage) they have to recall and replace all the ones that could potentially go wrong.
Remember MS had to do a massive recall/replacement programme for XBox power cables a while back?
I think there had only been a couple of cases of them causing a problem, but due to the potentially serious consequences of the problem they had to replace every cable from the same manufacturer.