Your analogy breaks down a bit because you can't really lose a car the same way.
Let's assume a different sequence of events, to help separate the issue of trade secrets and stolen property. Let's say that the phone was left behind at the bar, someone picks it up and hands to you, thinking your friend, who is currently in the wash room, left it behind. You've had a couple of beers and you know your friend has an iPhone, so you put it in your pocket for when he comes back.
10 minutes later (there was a line) he returns and you order another round, forgetting about the phone in the process. You don't remember you have it until you get home at 3am, having had a few more glasses of "golden liquid" (as Gizmodo would refer to it).
Realizing you have someone's phone, and it's probably not your friend's, you turn it on, seeing the last thing the guy used before leaving it behind: his Facebook page. Good, you have a way to contact him. You thumb through the apps, try the camera, and then decide to go to bed.
In the morning, you wake up groggy, and find the phone has bricked itself overnight. You didn't write down the name from the Facebook page because, well, you were drunk. So now what? You are now in possession of a "lost" item, meaning that, according to California law, you are "a depositary for the owner, with the rights and obligations of a depositary for hire."
While pondering your situation, you notice something odd about the device. It looks like a 3GS with a case, but the buttons aren't the right shape. You take the cover off to investigate. It is immediately clear that this is not a 3GS. Knowing you have something interesting on your hands (even if it's a fake) you grab your trusty Nikon, and photograph the device from every angle.
Once you're satisfied you have good pictures of it, you put the case back on and head down to your local police station to turn in the device, as required by California law. When you get home, you sell the photos you took to Engadget for $500.
According to my (limited) understanding of trade secret law, Apple would have no case against you on the basis of trade secrets because, by bringing the phone out in public and leaving it behind at a bar, they clearly did not make reasonable efforts to keep it secret.
Of course, the events of that night aren't nearly as clear, but, unless Apple can show that the phone was not lost but stolen (and not technically stolen because the guy misappropriated lost property, but stolen from the guy's pocket) there is no basis for a trade secret suit.
This whole narrative leaves out the potential for other charges, like criminal theft by misappropriating lost property, or a civil suit against the "finder" for misappropriating lost property, but that's kind of the point. I'm trying to separate the issues so we can discuss them a little more clearly.