Could the option to start recording based on louder sounds be explored? I know that Logitech was looking into this with their circle cams some time ago.
Let me elaborate, on of my cams is looking at a acrylic roof hatch. The roof itself is accessible for other people, so I want to be as sure as possible I pick up motion at my hatch. If people walk on the roof you can clearly hear it, so that might be a good trigger.
The same goes for someone that tries to break a door or the hatch for instance.
Another thing might be to be less reliant on only the PIR sensor, which I think HKSV does as well. I will gladly sacrifice some extra battery life, to enable such thing in the future.