You may have knowledge of the Fazio's operation I have not heard before, I'm curious if there is an interview or document which explains the details of their operation. The description of their business in their WA articles of incorporation(attached here I think, still new here so not sure the file attachment works) seem to suggest harvesting sand/gravel from pits and/or brokering sand/gravel from others is on the table.
Don't you feel one packet fully exposed to the elements and not shielded by the bag and surronding money would deteriorate much more advanced than we see in the bundle? Also, the probability of catching a ride on a log or mound of drift would drops with the single packet.
As with most things in this case, speculation is unfortunately the only route here but certainly some scenarios have much higher probabilities than others.
Fazio Sand and Gravel Articles of Incorporation WA.pdf