So, Pres Trump, in reference to the sanctions about to hit Iran, tweeted, "Sanctions are Coming," which is obviously a play on "Winter Is Coming" from Game of Thrones.
The article I read said, "HBO did not say whether they would pursue legal action..." which, assuming the article is not going off a cliff, leads me to believe that HBO thinks it may have a legal claim.
How could they? If I record a vid (which I then later post on the net) of me standing on my porch as the sun is setting, during which I say "Night Is Coming".... or if I stand outside as snow is falling, and say "Winter Is Coming"... HBO can't sue me for that. Can they? How?