If your friend or family member goes into a murderous rage and rips it all up and shouts and jumps up and down. "I will find out who wrote this and KEEL them". Then you know NOT who to trust with your apostasy.
In all seriousness though, I think the idea of leaving that sort literature in a public restroom is an interesting idea. After all, a bathroom stall is one of those rare places where a person can feel completely and totally alone, even when there are others in the restroom. And the fact that they're there means they will have to spend at least a few minutes there, even if they disagree with the graffiti on the walls or, in this case, the anti-Islamic pamphlet. And even if they disagree, even if it makes them angry, they might read something that makes them uncomfortable--plants a seed in their mind that might someday grow into something more.
Or they'll just ignore it, flush, and go about their day. But at least there's a chance.