This is the idea of what a supervisor can do to prevent problems with substance abuse in the workplace. With a clear set policy there is no excuse that an employee can use to avoid the rules. Privacy Protection and privacy deals with the idea of human rights. Privacy, in the sense of suspicious individuals, is declared as Civil Rights to an employee in the United States. Random drug testing is protected in our civil rights and is almost impossible to touch for a company's interest.
Civil rights protect an employee from getting laid off the job.
Also, drug testing in the workplace must be random or else it is infringing on privacy. In an article on the Internet, they discuss the idea of unfair testing. Also drug tests tell more about a person than just use of illegal drugs. An employer can find out whether a person is pregnant or taking prescribed drugs. Thinking on behalf of the company is a smart way around things but infringing on the privacy of employees is risky.