Essentially, I'm looking to release a piece of software as "Kopimi". I want to release it into the public domain so there is nothing stopping someone from using my work. However, can I still be held liable, since it doesn't explicitly release the author from liability?
The Wikipedia article you linked to notes:
While Kopimi may appear to be a radical free content license, in effect similar to Creative Commons Zero, no one associated with Piratbyrån ever called Kopimi a license, instead describing it as a symbol of certain ideas. The website of Kopimi contains no terms or legal text. The Open Source Initiative, Free Software Foundation, or any other organisation within the open-source movement, does not list Kopimi as an approved license.
The Kopimi symbol is just a symbol. People sometimes use it to mean, "Please use this however you like and I promise not to sue you," but it's not clear to me if a court would enforce such a vaguely implicit promise against you, the author, if you changed your mind and did decide to sue someone. This isn't a condemnation of the Kopimi symbol by any means, but merely my opinion that the Kopimi symbol is not a license (nor an acceptable substitute for one).
If you really want to license your work freely, then actually attach a license to it to promise a clearly-defined set of permissions to all your recipients. If you want to impose no restrictions on downstream distirbution and modification, I highly recommend CC0 (combination license and public-domain dedication) which is recommended by the FSF and by Creative Commons for use on software. The CC0 license/dedication includes a disclaimer of liability.
Note that CC0 does not license any patent rights you may have in the software. CC0 is only a copyright license. If you want to license your patent rights, to assure recipients that you will never hold them liable for infringement of one of your patents, the Apache 2.0 license is a permissive license that grants patent rights. However, it still requires attribution, which may be more restrictive than you want your absolutely-free license to be.