Headlines are just too short or insubstantial to be considered capable of copyright protection. No matter how creative they might be.
Anyone involved in marketing will understand that the 'hook' in advertising can mean the difference in 10s of sales and 1000s of sales.
All the same, there are times when you just wish you could stop other people from using a really good headline, and Fairfax Media agree!
Not subject to Copyright
Fairfax took the Australian Financial Review (AFR) to court over a headline. It must have been a good one. They have lost the first round, but at the time of writing could still appeal.
You might wonder why, with all the effort that goes into creating a great headline, there is no protection. One arguement accepted by the court is that every bibliographic reference would then constitute a breach of copyright. After all, how many unique title combinations do you think there are?
The release of James Cameron's Avatar at the time it was released forced the change in title of "The Last Airbender" based on the "Avatar: The Last Airbender" animated series.
So if it's short, don't assume you have copyright protection.