IANAL
Absense of evidence is not evidence of absense. If the video had been continous (contiguous) with no gaps, and covered the area, it might prove that the accused was not present. As there ARE gaps, it can't, and thus is not suitable to use as "evidence of absense".
If, instead, the accused could acquire video from a system at his alledged location, and that video showed him there, irregardless of gaps, it might be admissable.
I am not sure that in a case regarding a restraining order (the 2nd), that it would be severe enough to get a court order for the phone company to surrender tower information. And even if they did, it would only prove the location of the phone. Not of its owner.
I just now saw the Kendrick Johnson case, which is a lot more tragic. It's mind-boggling to me that you would spend a small fortune on a surveillance system that only "just might work" when you need it. The CNN report alludes to the idea that someone tampered with the evidence. That's obviously a lot more dramatic and exciting than saying that the system was shit not too "user friendly".
As it turns out, running the systems with no time sync, 1 fps, and poor motion detection setup made it real hard to determine what went on when something did go down. The lack of time sync and 1 fps are smaller problems than the poor motion detection setup, which leads me to one of my pet peeves :
There are too many damn options!
Each option is a small trap for the integrator to fall into. And to make matters worse it's really difficult to validate the settings. Anecdotally, I spoke to an integrator recently; he always sets up for continuous recording, because he doesn't have time to sit there an tweak the motion detection settings properly. I think he should be going from ultrasensitive to insensitive aiming for just above "too sensitive", but what if you don't, what if you go the opposite direction and stop just as it triggers on some random person walking by at that instant. How do you know if someone walks by and don't trigger motion. How do you know if it picked up every single person that walked by 24/7, 52 weeks of the year. Taking rain, snow and fog into consideration. What about people moving slowly, or fast and so on.
Then when you are done playing with motion detection, you can play with the quality settings, bandwidth settings and so on, and hopefully you don't cranck up the compression to squeeze in more days on the harddrive, while making the image quality so piss poor bad that you might as well have installed a 640x480 USB camera from 2002.
With that said, Happy New Years folks!