The procuring, warehousing, shipping and selling of opium required many grunts. You don't keep secrets about matters that are a major trades item. What's interesting is the varnish that's been put over the trade that brought on the Opium Wars around the time of the American Civil War. The South has maintained that the war was about 'states rights." The story about the China trade has been painted as about "free trade.' In truth, the Brits, Portuguese and Americans were just drug runners, no different than the Columbian cartel. The opium propaganda was so successful that Mark Twain would write:

The ingenuity of the Chinese is beyond calculation. It is asserted that they have no words or expressions signifying abstract right or wrong. They appreciate "good" and "bad," but it is only in reference to business, to finance, to trade, etc. Whatever is successful is good; whatever fails is bad. So they are not conscience-bound in planning and perfecting ingenious contrivances for avoiding the tariff on opium, which is pretty heavy. The attempted swindles appear to have been mostly, or altogether, attempted by the Coolie passengers - the Chinese merchants, either from honorable motives or from policy, having dealt honestly with the Government. But the passengers have reached the brains of rascality itself, to find means for importing their delicious drug without paying the duties. To do this has called into action the inventive genius of brains equal in this respect to any that ever lodged on the top end of humanity.

So the Chinese were excoriated for doing retail, what had been done to them wholesale. [See] http://www.historytoday.com/julia-lovell/opium-wars-both-sides-now