All I see are risk: very low, code freely posted meaning patches the next day, and I see 0 (thats right, zero) occurances of anyone ACTUALLY being infected just by doing their usual thing on the computer. Download and run it? Sure, then this would count as a Linux virus:
sudo passwd root
0n0z I just wr0t3 t3h f1r57 1!nux \/!ru5!
It t3h changes t3h root password and hij4cks t3h j00r comp00ter!
Please, your pitiful Windows OS gets infected just by using Internet Explorer, and the most you could come up with as a virus for Mac's are proof-of-concept viruses that infect no one but the people who download and test it, that or lame worms that go through and destroy Windows boxes, and along the way do no harm to the Mac/Linux box. 0n0z! Here's t3h an0th3r V!ru5 and it's for Linux AND Mac!
sudo rm -R /