Empty Luggage on NYC Subways?

Okay, earlier, I was flipping through the channels and Fox News (aka Faux News) was running a piece with reporters claiming that large numbers of empty pieces of luggage had turned up in NYC subways lately. The fear being that terrorists were planning a repeat of the Madrid bombing. In looking at cnn’s website, I find no mention of it, nor can I find any mention of it on Fox’s. So, has this been occuring, or was it just “filler” on Fox?

N.Y. SUITCASE SCARES SPUR TERROR ‘DRY RUN’ FEAR

Given that it’s in the NY Post, I’m surprised there are no exclamation points in the headline.