also responsibility will not be assigned if the code causes problems

Oh, it will be assigned. Trust me. Either Perl Monks itself will get hit, or someone will demand the identity of the person who posted the code.

Also, if you haven't noticed, people like receiving credit for their work. A system where you aren't acknowledged for your charity work will not survive, guaranteed.

I think it would be important to put a "You may have donated money for this, but use at your own risk" clause in there somewhere.

Doesn't matter. Somebody's still going to have to pay legal bills. Many supposedly free societys still have this problem. It doesn't matter if you're right or wrong if you can't pay your lawyers.