We can’t unlearn what is learned, although we do have the capacity to change how we use knowledge, to improve or deteriorate ethically. From a story about civilian drones in the Economist:

“Safety is not the only concern associated with the greater use of civilian drones, however. There is also the question of privacy. In America, at least, neither the constitution nor common law prohibits the police, the media or anyone else from operating surveillance drones. As the law stands, citizens do not have a reasonable expectation of privacy in a public place. That includes parts of their own backyards that are visible from a public vantage point, including the sky. The Supreme Court has been very clear on the matter. The American Civil Liberties Union, a campaign group, says drones raise ‘very serious privacy issues’ and are pushing America ‘willy-nilly toward an era of aerial surveillance without any steps to protect the traditional privacy that Americans have always enjoyed and expected.'”