What is the consequence of Rule 9-1(4) of the Rules of Civil Procedure when a plaintiff loses at trial?

… what happened here is that the plaintiff, well aware of the significant credibility issues at stake, chose to gamble or "take his chances" by going to trial and lost. He should live with the consequences which Rule 9-1(4) seeks to avoid: Wafler v. Trinh 2014 BCCA 95 at para. 81.

On the other hand, in Khunkhun v. Titus, 2011 BCSC 1677, Willcock J. (as he then was) reached the opposite conclusion after a jury trial in which a number of credibility issues were involved. He said:

... No aspect of the claim advanced was frivolous. The plaintiff did not unnecessarily lengthen the expense or duration of the litigation. To use one test, I do not consider that reasonable counsel aware of all of the evidence in this case but unaware of the jury award ought to have encouraged the plaintiff to accept the offer at the time it was made or up to the date of the rendering of the jury's award. I do not regard this as a case where the plaintiff should have freed up the judicial resources used to assess her claim. I am of the view that the plaintiff might have made a careful assessment of the strengths and weaknesses of her case at the commencement and throughout the course of this litigation and not accepted the settlement offer that was made to her. In summary, I find that it was entirely reasonable on the evidence for the plaintiff to prefer taking this case to the jury to accepting the offer that was made to her before trial. I adopt here what was said in Sartori v. Gates at para. 67: The plaintiff had the right to test to the extent of the range of damages by trial adjudication.

In Paskall v. Scheithauer, 2012 BCSC 1859, the defendant did not provide any expert reports of her own. N. Smith J. declined to award double costs because the defendant provided no evidence against which the plaintiff could judge the reasonableness of the offer. He stated: