A long time ago in Blockland, someone put a very malicious backdoor in a wide-spread add-on that gave him eval access to your server and allowed him to do things like remotely open up URLs on your PC by tricking your client into thinking that you clicked on a link even though you never did. The person (I think his name on BL was Anti-Christ) joined my server while I was hosting Isar Tower for IcyGamma as we were working on it. The guy cleared all bricks, opened up 100+ windows of meatspin, de-admined all of my admins, and then he forced my BL to shutdown. I was pissed that I lost all the progress I had made with Icy and I was paranoid that it would happen again.