If you ignore the request for salary requirements altogether, it could also weed you out and prevent you from getting an interview because you didn't follow the employer's job application directions. (topresume.com)
This technique is used to make screening easier — if someone can't follow simple application directions, why waste time on an interview? (biginterview.com)
In any case, be sure to address all the points and questions raised in the application directions. (sciencemag.org)