I'm looking at add a hard-wired dashcam to my vehicle. I have the fuse tap ready (And appropriately guarded for now) and am looking at the ground for the hard wire kit. I got in near the fusebox and see a previously added fuse tap (for what I believe is the dvd head rests, and since this was part of the original sticker I assume the dealer installed these prior to initial sale) and the ground for this additional accessory is at a location used by the car's factory wiring.
I was always under the impression that when adding aftermarket accessories, you should find a point that is unused by existing grounds, because combined grounds might cause unintended feedback loops, but given that it looks like the dealer may not have followed that rule (and I can't say for sure where I picked it up) I'm curious now if it matters.