<p>It says optional, but do most people fill it if they have it?</p>
<p>it's a personal choice, given all the security issues surrounding identity theft. However, it is useful to the folks in the mail room to help get your paperwork into your file. </p>
<p>When my niece applyied to UNC, another girl with the same name also applied. It just so happen that they also went to a school with the same name, but different city. In both cases, paperwork ended up in the wrong folder and took numerous calls to sort it out.</p>
<p>Most do because if you're applying to some schools it really slows down your FA process. :p</p>