Say I make software and release it under the WTFPL. Then, someone uses it and it causes their computer to catch fire. I did not design my program to catch their computer on fire, and in fact it might be too simple to do so. Still, they bring me to court. Does using the WTFPL (or otherwise placing the product in the public domain) offer any protection? I ask this especially because it seems to often be used as a minimal license where it's not legal to release the product in the public domain, effectively placing it there.
My biggest reasoning is imagining pencils. The design of a pencil (graphite embedded in wood with rubber on top) is in the public domain. If my arm swings into the pointed tip of a pencil, I don't sue the person (or family of that person) who invented the pencil. If anything, I sue the person who sharpened it, who placed it there, or who manufactured that particular pencil.