In a 1986 Supreme Court case, justices were asked whether a police department violated constitutional protections against illegal search and seizure after it flew a small plane above the back yard of a man suspected of growing marijuana. The court ruled that "the Fourth Amendment simply does not require the police traveling in the public airways at this altitude to obtain a warrant in order to observe what is visible to the naked eye."
In a 2001 case, however, also involving a search for marijuana, the court was more skeptical of police tactics. It ruled that an Oregon police department conducted an illegal search when it used a thermal imaging device to detect heat coming from the home of an man suspected of growing marijuana indoors.
