Black Market Urine

Sales of clean urine, to avoid being busted during workforce drug tests, are doing well in Alberta, apparently. What I want to know is, where do the hemp companies that sell the pee, buy the stuff from? (Assumedly their own pee is not very clean). Do the pee-ers know what their pee is being used for? Do the people who sell the the pee ever lie and consume drugs themselves, selling bad pee? Are the people who buy the pee forced to do drug tests on it first, or on the pee vendors, to guarantee their product? It would be amusing to me, if people who are selling pee to help others pass drug tests are themselves subject to drug tests. Perhaps they buy pee to help foil them...