Shorten the battery life? How would that work?
While i doubt it the chargers may supply less than their rated current but that would only mean slower charging.
To shorten battery life you would need overcharging ... which would be dangerous and highly unlikely as the charge-controller is not even in the wall adapter but rather the device.
As there are dangerous and EMI emitting wall adapters out there higher standard chargers would of course be a good idea.