Which could be an issue if you have one camera with and another one without. I find the camera WITHOUT GPS is gaining a minute in time ever month compared to the camera with it. I had my cameras synced to the second, which is a little tricky if one or both don't have GPS, but not a problem if both have GPS. When I had an incident I wanted to make a video, I found my rear camera was a minute and 10 seconds ahead from my front camera. This a little over a month after I synced them. My front camera (the one with GPS) and cell phone have the same time, perhaps 1/2 a second off at most.
Having 4 cameras in my car not with GPS,and with time / clock not synced up i have to resort to recording # in a given driving session.
This sort of work okay as to finding what i need and stitch it together in post production, but i have had to leave out the time/date stamp in those cameras as the not synced time would annoy me.
I am looking forward to getting 2 of the cameras in sync at least, the GPS make things so much more easy.
And i am okay with GPS in a dashcam, on the other hand in my phone i dont use it often and i sure as hell dont have it on all the time as some / many people have.
And H2O dont fear the GPS, if you are worried about some one using the footage against you, well then you should not video your drives as your speed can always be determined from the video footage itself.
Distance traveled in ? time, go measure the distance between 2 fixed things in your footage, time how fast you cover that distance, add a little math, and you have your exact speed.
Like many users, I used the emergency (I think event is a better name) button. If I saw something in the rear view mirror back in the days my 2 channel camera worked, well I had video on both cameras. Now that I only have a single channel camera in the rear, I rely on the front camera to mark incidents, whether its an accident, near accident, something stupid or something nice like a deer crossing. My arms just aren't long enough to use the event button in the back as I drive, so its the front camera to mark events
In Toronto, its a not a big deal to determine where you need to look as there are many land marks and I am familiar with commute. This would be a challenge driving thru a forest or farmland. It helps to have cameras in sync. Even if your camera does NOT have an event key, its good to have it closely matching the clock in your car.
My two channel camera had clock issues as it switched to parking mode. This was an issue when I was using it as a security camera to catch a vandal when I was working my two neighbours also effected by this as we tried to establish time damage to property was occurring.
Android default clock app doesn't show seconds of the minute, but the app "Alarm clock for me" does. I use that to sync my rear camera.