Do you have any idea if Berg was in the country at the time the film was being shot?
Actually, I lean toward Cicero's verdict, just a kid looking for himself. Reminds me of Johnny Walker Lindh, in a way. They both seem rather naive about the people they were dealing with, and both trying to find themselves on the far side of the moon, so to speak.
Actually, at a certain age I might have been tempted to go and roam about in the way Berg did, similarly trusting in the good nature of strangers for my safety.
He ad been there when Moore was filming, so that is a possibility.
But he wasn't working to get footage for that film when he died, which is what people want to be true.
When I was 18 I went to England, bought a bike, and spent three months cycling around Europe, with a ground cloth, a sleeping bag, and a spare set of clothes. I think I spent $600 for the summer, $300 for living and traveling expenses and $300 for a Leitz microscope I had promised to bring back for a friend of mine (for which I was reimbursed).
That was before the days of hippies. I just spread my bag in the woods, behind the bushes in municipal parks, and the like. Never had any trouble.