I say signing is not necessary.
I realize states and countries are a bit different, but for the most part, a company post a job, people apply, and the company offers the job to the most qualified candidate. The candidate takes the job (or turns it down), and works there until they quit, or the organization let's them go.
What value is in there for anybody to sign the job description? What is it "proving"? To me (this is just an opinion) when you have people sign things, it's like you're making some legally binding document.
The candidate should be adequately interviewed/ verified by the hiring agency prior to offering them the job. Is the person qualified (or most qualified) for the position?
Then the candidate should investigate the organization, hiring supervisor and such, to assure that the job is what they want.
I'm sure I signed my marriage license. But my marriage (and a successful one up to this point

) focuses on things significantly more important than the words on that paper.
