Good to know. I don't have high requirement for a dashcam so a basic one will do. After talking to the sales person I've changed my mind and will go with a single dash cam plugged directly to the cigarette lighter. If hardwired to some parts of the car such as battery, will void the warranty for battery with new cars. Initially thought of fixing both front and rear dash cam but reverted to just front to avoid the hassle and also the fact that the rear windscreen would have  very dark tint so the rear dashcam will not be able to capture a clear video if the tint is very dark.

The moment dashcam are hardwired outside of manufacturer service centre (not car manufacturer endorsed product), then it WILL usually void electrical warranty, once caught. Not all warranties, meaning chassis warranty, engine warranty, etc all still working. If you can removed traces of hardwire before sending to SC for any electrical warranty claim, can lar...just don't get caught.

One of way is to installed an OBD hardwire instead of fuse hardwire, plug and play.