Smith v. Maryland, 442 U.S. 735 (1979).
The Court rules to uphold the use of pen registers.
California v. Ciraolo, 476 U.S. 207
A naked-eye observation by police officers of a back yard (curtilege) does not violate a person's protected reasonable expectation of privacy.
Chief Justice Burger delivered the opinion in this case involving a warrantless search for marijuana plants by police helicopter.
"Any member of the public flying in this airspace who glanced down could have seen everything that these officers observed. On this record, we readily conclude that respondent's expectation that his garden was protected from such observation is unreasonable and is not an expectation that society is prepared to honor."