Sometimes, headlines can be really confusing. I just saw this headline on the Guardian online of Tuesday, 16 February, 2016. (Although it is two months old, there is a link to it from a current article.)
When I read it, I thought, "That's good. Donald Trump is supporting the Paris deal, and he is warning people that it should not be scrapped."
Unfortunately, that is not true. In fact, 'warned' is a passive verb, so the true meaning of the headline is, 'Donald Trump has been warned about the danger of scrapping the Paris climate deal'.
I wish that headline writers would think a bit more and make their headlines clearer. Or maybe they do it deliberately, to get us to read the article and find out what is going on.