If I'm ever confronted by somebody with a poster like this, here's what I will do: I will politely ask that person to tell me, in plain spoken language how I can stop rape, using the information on that poster. Afterwards, I'll ask if he/she believes she has made the world any safer by giving me that information.

Think about it, can you imagine reading that thing addressed to an individual? "Hey, did you know that you could stop the next rape from occurring? Have a buddy with you, he can stop you if you try to rape someone!" Maybe, just maybe this would make them realize they are accusing all men of being rapists.

Discrimination: Painting with a broad brush an entire population for the actions of a small minority, making claims about the entire population that you would never accuse an individual member off.

edit

Yes I know this poster is a parody of "victim blaming/rape prevention advice for women". But the notion of "men can stop rape" is still alive and kicking, moreso, the idea that all men are potential rapists or child molesters is ever so ingrained in our society. Just look at the latest craze of airlines removing from seats next to unaccompanied children.