There are adults weighing 170 lbs and under. Looking around my
neighborhood and office, however, there's not very many of them. Some
of this is based on height (hard to be 170 lbs and 6' 3" for example -
but yes, not impossible), some on the documented weight gains in
America. So, based on my admittedly anecdotal evidence on average
weight, my initial thoughts on this are that it's likely to be an
overgross situation.

Perhaps you live in an area with a lot of 170 lbs and under adults.
Good for you. Since this situation seems likely to be a smuggling
situation, it's pretty clear that a valid W&B isn't the prime
consideration for the pilot. I guess your own excellent imagination
didn't extend to seeing my indended tongue-in-cheek quality to my post.
Perhaps I should have been more clear.

-Malcolm Teas