If a petition meeting the requirements set forth in RCW
53.04.150 is filed with the commission, the commission shall determine a date, time, and location for a hearing on the petition and shall provide public notice of that hearing and its nature by publishing the notice in one issue of a newspaper of general circulation in the district and by posting the notice in three public places within the territory proposed for annexation. The commission may require proof of a petition's authenticity before complying with notice requirements imposed by this section and may require the signers of a petition to bear the costs of publishing and posting notice.