I will agree that the systems that do not give any form of notification that have occurred while parked are flawed in this regard.
On the other hand, depending on how you have your parking guard set up it might also be a nuisance, say you use motion detect, well when you get back yo your car you will probably hear " there have been 387 events "
And as you can not find any dent in your car, you will probably soon ignore that or turn it off.
So event notification should probably only be there if the G-sensor have been triggered, and i could use that even if i use always record low bitrate for parking guard, CUZ i still have G-sensor on too, just to actually detect / flag any actual events.
Which is nice even if i only use parking guard for 3 hours and so without G-sensor i only have 3 hours of footage to look thru to find the event.
TBH i will actually prefer a smart camera with instant notification to my phone, so i can react at once things happen.
I am right now going to look over my CCTV footage, CUZ someone have folded on my side mirror while my car was parked, not that it in itself matter but i am still curious who did it and then not just put the mirror back where it belong, CUZ it is someone that have walked in between my car and the bush i park right next to.
EDIT : Okay that mirror thing happened in the car wash yesterday, i just did not notice before now