Awesome sign.I also sent you an e-mail.
This is a good idea. From a designer's perspective though, I think the poster is a little "busy", as in there are too many words. The message should be very clear and brief. Also, references to murderers and rapists are good, but references to druggies and thieves will confuse the issue. After all, we don't draw on a person for bare theft, or for being on drugs.
To convince, it's ultra-important not to overstate the issue. Otherwise we simply cement the opinions of the opposition. With a few revisions, I think it would have pretty good value, especially placed on the entrances to university buildings.
Mind if I make a few changes and post a revised version?