It can't happen here comes to mind. You are more optimistic than I am. I do believe most people are good most of the time.

But that doesn't mean bad people don't exist.

The Atlantic: For people struggling to put food on the table and a roof over their heads, "voluntary" participation in clinical trials is a slippery slope.
In 2008, the Center for Research on Multinational Corporations released a document full of examples of the detrimental effects of unethical clinical testing that went on the 1990s and throughout the 2000s in the developing world. The report included the case of clinical trials in Uganda between 1997 and 2003, when women taking the anti-transmission drug Nevirapine experienced thousands of serious adverse effects (SAEs). These symptoms went unreported and testing was allowed to continue, resulting in the (also unreported) deaths of 14 women. In Hyperabad, India in 2003, eight test subjects died during the testing of the anti-clotting drug Streptokinase. The worst part, though, was that the subjects did not even know that they were part of a trial.

These two cases are just a couple out of numerous in the report, which is only one of numerous reports of unethical clinical testing on the world's least privileged people.