Can an offer of settlement be marked "Without Prejudice"?

I refer to the comments of Fraiberg J. in Ferlatte v. Ventes Rudolph Inc., [1999] Q.J. No. 2735, where he held at para. 13: The same objective of forestalling needless conflict justifies that communications tending to prove settlement should see the light of day rather than be entombed by privilege. Therefore marking correspondence "Without Prejudice" does not by itself assure the protection. Rather, it is the contents of the correspondence that determine the matter. Offers of settlement and ancillary communications are therefore presumed protected until acceptance, even without the warning. By the same token, the protection vanishes despite the presence of words that announce it, once its purpose has been realized. Put simply, the words "Without Prejudice" or expressions to similar effect are not really necessary on offers of settlement, and once the offers are accepted, they are useless.