I've heard and used the phrase "blow up the bathroom" numerous times in my life and not once have I ever thought the phrase had anything to do with explosives. I'm guessing that's not a saying in New Orleans because a man was recently arrested at Willie's Chicken Shack after he told employees:
"Y’all about to close right now because I’m going to get a bomb and blow this place up.”
The man claims he didn't mean it as it was interpreted, but was arrested any way... SOURCE