Using parking guard are also something new to em, only last year did a brand provide the hard wire kit for a camera they sent to me.
So for about a year i have used parking guard on the Street guardian SG9663DR, but i have now changed to use parking guard on the Viofo A139 system they sent to me a little while ago.
I only use parking guard for 1 hour ( on a timer in the camera ) this cover all my shopping and at home i have cctv on my car where it is parked.
In the SG camera the low bitrate recordings are just among the regular recordings, but the files are easy to spot on the PC as they are just 118 MB in size where as normal recording files are 350 MB in size ( for 3 minute files )
Last year when i got the SG camera i made a test with the car parked and using low bitrate, as i was not sure low bitrate would be good enough to capture plates on cars passing by, but that was no problem at all.
I have only tested G - sensor activation in my car on the SG model, but as i recall it dont change to normal bitrate as that would mean the camera would have to stop and change recording mode and so some seconds would be lost, so the files the G - sensor lock in the RO ( Read Only ) folder are just low bitrate too.
I would assume the A139 do the same
Low bitrate are regular video files with sound and everything, just they are in low bitrate to make the files take up less room on the memory card.
When driving and pressing the event button ( i do not use G sensor when driving as that is bad ) then the camera of course record in regular bitrate.
Both cameras can also record time lapse in parking mode, as i recall with 1-2-5-10 FPS, but then the files have no sound, and i assume the G - sensor if activated would just lock those away and so you would have no regular video after a accident in the parking lot only time lapse.
As i recall the A139 put the low bitrrate files in a folder named parking, so they are not among the regular files and so even more easy to find.
But as use small icon + file info when i browse a folder on my PC so also very easy to see what files are parking as i can see the size of the files while i scroll down thru the recordings.
Yes if you use parking guard a lot, it would be good to have G - sensor on to lock a actual event, and so act as kind of a beacon too, but there is a downside the G - sensor are not super sensitive so a person could key the whole side of your car and the sensor would not feel that, but then low bitrate would always be recording so it will see that, but then you will have to see the scratch to know.
Either camera do not give a warning when you get back to the car if there have been a event, this is a problem with most cameras i think but some do give a warning as i understand, and that is how it should be.
With the SG9663DR it is a must that you mount the remote unit on something solid so G - events can be picked up by it, i just have mine lying in the car so i can kick wheels and nothing happen, but drop a match stick on the unit and the G - sensor will feel that.
Other types are not having that "problem" as they generally mount on the windscreen glass, which are solid attached to the rest of the car, so shocks from other places of the car can travel to the G sensor to be picked up.
The low bitrate files are not locked so in time when the card is full they will get deleted to make room for new recordings, but having a sufficient large memory card will help with that.
I use 256GB cards in my regular cameras, and 128 + 64 GB cards for camera i test ( too expensive for a pension to buy large memory cards for testing memory card compatibility )