I have seen several parodies of future historians finding artifacts
from our time and giving them all sorts of significance they neither
possessed nor deserved.

David Macaulay's Motel of the Mysteries is a wonderful example
here about a 41st century archaeologist discovering a 20th century
motel room and his totally off-the-wall interpretations.

http://etext.virginia.edu/railton/enlt214m/mystmotel.html

However, I wonder how casual certain things were to certain
cultures? If the whistles were just whistles, why was one
buried in each hand of that skeleton mentioned in the article?

I would be surprised if that culture would bury someone with
something that was not of major significance in their lives and
especially for their journey into the next one. Even in our jaded
culture today people are buried with items that at the very least
meant something to them in this life even if it has no major
meaning anywhere else. For the ancients, the journey to the
next life was serious no matter what the culture, so I have a
feel that in this case at least these noise makers were a lot
more than just a way to make noise for the fun of it.