Homeless man swipes Corvette, joyrides to strip club: Police

"Had been reported missing"

Missing from where? He's homeless! Did no one answer when his neighbor knocked on his cardboard box?

"Top down, left keys in 1981 Corvette." To a car thief, this scenario is like shooting fish in a barrel. Prior to reading the article, the question that was initially raised in my mind was if this was one of the newer ones with keyless ignition. In those, the battery/ignition interface remains "active" when key fob is within range. If owner isn't watching it, thief could (conceivably) get in car, and drive off with fob in range.

it's actually illegal to leave your keys in the car in some states.

Texas, I know is one. It's called a "gateway" crime because stolen cars are often used to commit more serious crimes and at least 40% of all auto thefts were because people left their keys in the car.