I wanted to let everybody know, since it isn't commonly known, that pretty much all cars past 2005 contain a hard drive which records location, acceleration, and other data. They are commonly used in car theft cases and insurance claims. From the forensics guys I've talked to, they noted that some modern systems phone home to the manufacturer, but that data is rarely made available to the police. You pretty much cannot buy a modern car without one of these hard drives. Stay safe and if you have questions I can try and answer.
I haven't heard of anyone using this to prove that someone was at a protest ect, but I would expect it in the future. The cops do need a warrant for this and because getting to the drive is a fairly destructive process, they will (generally) actually get one.
They are located in the infotainment system, usually on the passenger side of the car's firewall. The exact location of the hard drive varies. They are usually in the unit behind the screen, and require near complete disassembly of the whole unit. Some vehicles have separate screen and compute units, the hard drive will likely be in the compute unit. Some vehicles may operate without them, but some may not. It is not well documented.