A better solution would of been "This firmware update identifies the use of 3rd party batteries and alerts the user to the risk of using them. It monitors the voltage output and shuts down the camera if it determines that the battery is insufficient or possibly dangerous. And invalidates the warranty too". This would of left open the choice to the user - after all there are a great many very good 3rd party batteries and they have saved my bacon in the past.
By monitoring the voltage I mean the camera can detect an abnormally fast voltage drop against its usage that might mean a defective or damaged battery - naturally it cannot detect if the battery is about to get white hot and set fire to the camera, but hey the user was warned and the warranty invalidated. I would expect the manufacturer to check the damaged camera EEPROM and say "aha! according to our data log you used not panasonic batteries, thats no repair for you!".
By removing the element of choice they raise the natural suspicion that this decision was taken on commercial grounds, not safety and risk a consumer backlash and dissatisfaction.