The law enforcement professionals in BC have created a website called BAITCAR.COM...where video cameras, GPS, and stuff are installed into cars and start recording when they're stolen. And...the results are broadcast onto their website. The criminals' faces are blurred, but their voices aren't distorted.
Well, I'm sure not an expert on this, but from what I understand you can tell anyway. It doesn't matter what's on the drive - even if it's been overwritten. You can still figure out what had been there before.