This nice studio picture of two Italian NCOs (I think the man on the right is a sergeant) lighting their cigarettes reminded me the legend of the “Three on a match” superstition. According to it, if three soldiers lit their cigarettes from the same match, one of the three would be killed or that the man who was third on the match would be shot. Since then it has been considered bad luck for three people to share a light from the same match.
The belief was that when the first soldier lit his cigarette, the enemy would see the light; when the second soldier lit his cigarette from the same match, the enemy would take aim; when the third soldier lit his cigarette from the same match, the enemy would fire.
Even if this superstition is known as a Great War one, there is an article dated 1894 which states that it was already spread in Rio Grande (Mexico) region.