I'm going attempt to carve some sort of middle ground and say that I don't think that there's anything wrong this sort of propagandising, but that building it all around grand ideals is going to lead you down a dead end. You might get the attention of a few people who are naturally sympathetic to your politics, but that's about it. It's a bit of fun, I don't disagree, a subversive wink to those who know what's up, but ultimately nothing more than that. (Personal confession time: when I'm bored, I write anti-capitalist slogans on money. It doesn't achieve a damn thing, but it makes me feel good to know that, at some point, somebody else will see that and get it. It's a coping mechanism, a way of dealing with the frustration of life under capitalism; valid within those terms, but nothing more than them.)
Instead, try to address more immediate, concrete issues concerning your student body and local area. Things that people are aware of, and they will have considered if only briefly. That helps them to realise that these are more general concerns, that they are not alone in realising that X, Y or Z is bullshit, that other people share their frustrations or disillusionment; in short, it can help open up a space, however small, for subversive communalities to emerge.
Revolution, y'see, doesn't become because people have all decided that it would be a good idea, but because daily life has become intolerable to them. This means that the role of radicals isn't to enlighten, but to push the situation to that sort of breaking point, and that means addressing concrete, everyday issues. The grand abstractions come later, as and when it's appropriate for them to do so.