From what I know back in the old days Lucky Strike supposedly would put a "lucky" cigarette in random packs, the "lucky" cig being pot laced and having some identifying mark so you'd turn it over so no one would know. Thus being a Lucky Strike, although the name actually comes from the gold rush. The pot thing is urban legend.
I see it as a tradition, although with smoking Luckies it's hard to tell which ones upside down.
