"Perhaps Susan was unjust in connecting Mr. Pryor's smile with the sinking of the Lusitania, news of which circulated an hour later when the mail was distributed.... [But o]ne thing is certain–Whiskers-on-the-moon said in the post office the day the news came, in the presence of witnesses, that folks who could not stay home after they had been warned deserved no better fate."
— L. M. Montgomery, Rilla of Ingleside. NY: Stokes, 1921, p. 139.
Censorship in Canada was particularly harsh among the Allied nations. Indeed, many were charged with (and convicted of) sedition for uttering such statements as "This was a capitalists' war of no interest to workmen"; "soldiers [were] a lot of bums and loafers"; and "you joined the war for personal reasons not out of patriotism." A person could be charged for simply possessing banned literature—even if they hadn’t read it. A person could also be charged for stating objectively verifiable facts that did not align with the war effort.
Although, as these headlines from the New York Times show, Mr. Pryor was correct in saying the passengers had been warned, his words might be seen as spoken in bad taste.
However, with the severe censorship regime in place during the war, they could easily have landed him in court charged with sedition.