What is the effect of issuing a writ of hare before an alleged unlawful detention begins?

Where the writ is issued after the alleged unlawful detention begins, the applicant is frequently left in the same place pending the return, often because the most important consideration is a want of alternatives. However, as in this case the writ can be issued prospectively prior to an imminent detention that is said to be unlawful. See Idziak v. Canada (Minister of Justice), 1992 CanLII 51 (SCC), [1992] 3 S.C.R. 631, [1992] S.C.J. No. 97. Here, too, the court must carefully balance the relevant considerations in exercising its discretion.