I'm thinking about posting a question/challenge to come up with a "sneaky" plugin, one that looks innocent, but can do stuff behind your back. I was inspired by the many filters in the plugins page: from a cursory glance it seems to be possible to "fake" an uninstallation, so that the site administrator might think the plugin is gone, but it is still there.
The benefit would be that we can learn more about WordPress, show off our coding skills, and maybe even improve the security of WordPress in the future by checking for these patterns. It could also attract more developers to the site, and maybe they even stay around to help others. The downside would be that malicious users could learn from it (but I don't think a smart evil hacker needs WPSE to learn the tricks), and that people could see WPSE in a negative light.
What do you think? Would such a question benefit or harm the site?