Do the police act improperly if they search, without warrant, the contents of a rubbish bag left on a property by the fence line for uplifting by the official garbage collectors? This was the issue in R v Patrick  SCC 17 (9 April 2009).
The police action involved a trespass: the act of reaching into the air space of the property occupied by the appellant, and uplifting the bag, which had been left on a stand in an opening or indentation in the fence at the boundary.
In the bag was evidence of ecstasy manufacturing, and the appellant was consequently convicted of unlawfully producing, possessing and trafficking in that substance.
There had been six such searches, on separate days, of the appellant's rubbish bags, and information obtained was used in support of an application for a warrant to search the address.
For evidence of serious offending to be excluded on grounds of unreasonable search it is necessary that it was obtained by means that were seriously improper. That is, exclusion of the evidence must not be a disproportionate response to the impropriety. On that basis the evidence here was admissible. Arguing otherwise requires asserting a serious impropriety, which in turn requires asserting breach of a significant privacy interest.
Abella J came closest to recognising a significant privacy interest. She delivered a judgment concurring with that of the other judges (delivered by Binnie J, appropriately enough as a cruel punster might observe), but reached that conclusion – that there was no impropriety – on the basis that the police had, before they searched the rubbish bags, reasonable suspicion that the appellant had been offending in this way. Such a threshold of suspicion was necessary, she held, because of the appellant's privacy interest which was "diminished ... not unlike the reduced expectation at border crossings" (para 90).
That, I suggest, is unsatisfactory, because it creates uncertainty over when a search warrant is needed. Border crossings are different, because submission to search is required.
The joint judgment gets to grips with analysis of privacy expectation, applying R. v. Tessling, 2004 SCC 67 (CanLII), 2004 SCC 67, 2004 SCC 67 (CanLII),  3 S.C.R. 432. There are three types of privacy interest: personal, territorial, and informational. This case involved assertion of territorial and informational privacy interests. Here, the interests were appropriately analysed as being informational. Issues were whether the appellant had a direct interest in the information and a subjective expectation of privacy in it; then, if he did, was his expectation reasonable in all the circumstances?
Here the conclusion was that the appellant had abandoned any reasonable expectation of privacy: he had done all he needed to in order to commit the bags to the municipal collection system. It would have been different (ie not unequivocally abandoned) if he had not placed the bags within reach of the collectors.
Accordingly, the appeal was dismissed. Only one, of all the 11 judges who considered this case, concluded that the evidence should have been excluded. Conrad JA emphasised the territorial privacy aspect and would not have permitted the totality of the circumstances test to diminish that, and also reasoned that people who leave garbage for collection expect it to be made anonymous by being mixed with other people's garbage.
Interesting issues were discussed, as is reflected by the participation of five interveners in this case.
What if the police had obtained the bags from the official collectors immediately after the bags had been lawfully uplifted? The availability of alternative lawful means of obtaining the evidence can weigh in favour of increasing the impropriety (as the police are expected to behave lawfully). But, arguably, the ready availability of lawful means should make the actual impropriety less, on a sort of "where's the real harm?" rationale.