The facts of this case are cut and dry. Some dumb slut put her $6,500 Rolex loosely into the security bin at Fort Lauderdale Airport and LEFT IT THERE. A minor league move if I've ever seen one; you stuff the valuables in a carry-on pocket, everyone working with a full set of chromosome knows that. Now, after she leaves the guy behind her in line eventually notices the watch. Initially, he looks like he wants to get it back to her until he flips it over and sees that "ROLEX" staring back at him. So he keeps it.
The question here remains: Is he a thief that stole the watch OR does this finders-keepers scenario remove him from any wrong-doing even if it was worth $6,500?
Before you answer, keep in mind that this might have turned out differently if he discovered a fucking Timex. For one, he'd have probably returned it. And second, no one would probably consider this stealing if he didn't.