More oppression of freedom in Australia

If compulsory voting with a fine wasn't enough the South Australians have now passed a law that bans anonymous political commentary on the Internet during election campaigns, the law states,

A person must not during an election period, publish material consisting of, or containing a commentary on, any candidate or political party, or the issues being submitted to electors, in written form, in a journal published in electronic form on the internet or by radio or television or broadcast on the internet, unless the material or the program in which the material is presented contains a statement of the name and address (not being a post office box) of a person who takes responsibility for the publication of that material.

Given the global nature of the Internet I wonder how they will stop people in other countries posting comments on behalf of friends?