what happened when the indians attempted to market their pearls collectively?

Juan Tomas, Kino's brother, tells him to make sure that
the pearl buyers don't cheat him. The Indians only deal with the pearl buyers in town,
and they  do not know what is being paid in other towns.  He tells Kino that before he
was born the Indians thought of a way to outsmart the pearl buyers and get more money
for their pearls.  They would put all of their pearls together and get an agent to take
them to the capital and sell them there. The agent would keep a share of the profit for
his trouble and give the rest to them.  The first man they hired to do the
job disappeared and was never heard from again.  Those pearls were lost. Then they hired
a second man to be their agent.  He was never heard from again, and those pearls were
lost.  So, they gave up the idea, and now they only deal with the pearl buyers in town. 
Kino says that the priest told him that it was against religion to do that. The loss of
the pearls was a punishment visited on those who tried to leave their station. Juan
Tomas says that he has heard the priest make that sermon every year.