Can a search warrant be used to determine the balance of competing interests between the individual and the state after the search has been conducted?

Hunter v. Southam at p. 653: If the issue to be resolved in assessing the constitutionality of searches under s. 10 were whether in fact the governmental interest in carrying out a given search outweighed that of the individual in resisting the governmental intrusion upon his privacy, then it would be appropriate to determine the balance of the competing interests after the search had been conducted. Such a post facto analysis would, however, be seriously at odds with the purpose of s. 8. That purpose is, as I have said, to protect individuals from unjustified State intrusions upon their privacy. That purpose requires a means of preventing unjustified searches before they happen, not simply of determining, after the fact, whether they ought to have occurred in the first place.