It's just an unfortunate set of events, not a crime.
Now, the "stolen goods", OTOH, could get them in trouble, but that applies to any phone ever left in a bar. I bet if I lost my phone in the bar, no computer crimes unit would be investigating. I'd probably just be laughed at.
Apple's phone should be no more special, under the law, than mine.
The difficulty there, however, will be proving that the phone is worth $400. If I pay you $10,000 for your toenail clippings, that doesn't make them worth $10,000. That makes me an idiot.
My estimate is that no charges will come of this. I also assume the guy at Apple won't be on the "testing our super-secret prototypes" team anymore.