[ryathal]

It doesn't matter. It's still just as illegal to get into an unlocked car or one with wide open doors without permission. The same premise applies to computers in a lot of places, access controls don't matter. If you access something on a computer not indented to be accessible, it's considered a crime.

[paledot]

Is it illegal, in fact? If a cop saw you, you'd be arrested and prosecuted for attempted auto theft, and your "I just wanted to see how comfy the driver's seat was" defense would ring hollow in court. But sitting in an unoccupied car without authorization isn't trespassing unless it's parked on the owner's land, and I'm not sure what other laws would apply to that specific act.