Page 82 - Privacy in a Cyber Age Policy and Practice

68 PRIVACY IN A CYBER AGE

used landlines, people mainly had phones in their homes and in enclosed
offices. These days, most calls are made on cell phones—over 70 percent of
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911 calls, for example, are made from cell phones —that people carry in
and out of private and public spaces, largely eroding the difference between
the two realms. The same blurring of the realms is evident in e-mails and
communication of photos. Moreover, cell phones, whether at home or in
public space, can be turned into listening devices even when turned off,
and computer cameras can be turned on to provide visual surveillance in
either space.
Moreover, new technologies such as high-power binoculars, aerial
surveillance tools such as drones, and thermal measurement devices make
it possible to learn details about the interior of a home or its curtilage without
ever physically entering either space. While the Court banned the warrantless
use of thermal imaging devices in Kyllo v. United States, one must expect
that in the near future technologies will be able to detect increasingly
small amounts of chemicals or electromagnetic radiation emanating from
homes. These technologies will enable private individuals, corporations,
and government agents to learn about matters in the home as if they were
conducted in open and public space.
All of this shows that the most important consideration when it comes
to protecting privacy in an age of exponential technological growth is not
where a person is, but rather what kind of information is collected. This
chapter next shows that if the information collected about an individual
is limited in volume, not sensitive, and not stored or combined with other
pieces of information, such collection will amount to a limited intrusion
that the courts should tolerate, even if the information is collected inside
private space by a public actor. By contrast, if the information collected
is of great volume, sensitive, and extensively stored and combined with
other information, the collection is likely to violate one’s privacy even if the
collection is only carried out in public. Such collection should be barred
unless there is a particularly pressing threat to the public. Before spelling
out these criteria for determining the scope of the personal privacy sphere,
I examine one previous attempt to form such a sphere on markedly different
grounds—an attempt that failed.

E. A Failed Foundation for a Personal Sphere of Privacy

As discussed briefly in Chapter III, in 1967, the Supreme Court departed
from its home-centric approach to Fourth Amendment cases in Katz
v. United States. This case concerned an FBI investigation in which the
agents did not obtain a warrant before attaching an electronic device to
record the sounds that escaped through the walls of a public telephone