Not back then it wouldn’t be, though, if we take the veracity of the story at face value. The inclusion of perfidy (bad-faith deception, such as dressing up as a civilian or opposing force) as a banned act within the Geneva Conventions was only adopted in 1977, under articles 37 and 39 of Additional Protocol I.
Edit: And even today, Article 39 exempts naval engagements specifically from that provision when it comes to flying the wrong colors with intent to deceive.
Not back then it wouldn’t be, though, if we take the veracity of the story at face value. The inclusion of perfidy (bad-faith deception, such as dressing up as a civilian or opposing force) as a banned act within the Geneva Conventions was only adopted in 1977, under articles 37 and 39 of Additional Protocol I.
Edit: And even today, Article 39 exempts naval engagements specifically from that provision when it comes to flying the wrong colors with intent to deceive.