Section 8 of the Canadian Charter of Rights and Freedoms protects an individual’s reasonable expectation of privacy from unreasonable state intrusion.
R. v. Tessling, 2004 SCC 67 (CanLII) at para. 18;
R. v. Orlandis-Habsburgo, 2017 ONCA 649 (CanLII), 352 C.C.C. (3d) 525, at para. 37.
State conduct that infringes on an individual’s reasonable expectation of privacy will be treated as a search for the purposes of section 8.
R. v. Buhay, 2003 SCC 30 (CanLII),  1 S.C.R. 631, at para. 18;
R. v. Spencer, 2014 SCC 43 (CanLII),  2 S.C.R. 212, at paras. 16-17.
In considering a reasonable expectation of privacy claim, the court begins by identifying the subject matter of the claim. It then asks first, did the claimant have a subjective expectation of privacy in the subject matter, and second, if so, was that expectation objectively reasonable, having regard to the totality of the circumstances?
R. v. Spencer, 2014 SCC 43(CanLII),  2 S.C.R. 212, at para. 18.
A subjective expectation of privacy is an important factor to be taken into account when deciding whether in the totality of the circumstances the claimant had a reasonable expectation of privacy. A subjective expectation of privacy cannot, however, be a prerequisite to a finding of a reasonable expectation of privacy. Otherwise, the protection afforded to personal privacy by s. 8 would shrink in direct correlation to the pervasiveness and notoriety of state intrusions upon personal privacy:
Tessling, at para. 42;
R. v. Orlandis-Habsburgo, 2017 ONCA 649, at para. 44;
R. v. Ward, 2012 ONCA 660 (CanLII), at paras. 86-87.
Section 8 protects the privacy interests that the citizen subjectively believes ought to be respected by the government and that society is prepared to recognize as ‘reasonable’.
R. v. M. (A.), 2008 SCC 19(CanLII), at para. 33, per Binnie, J.
A person has a subjective expectation of privacy where she believes she will be undisturbed because she is entitled to be left undisturbed.
R. v. Van Duong, 2018 ONCA 115, at para. 7.