Section 45. Right to membership

Upon the employment of any employee whose
  right to membership in a public retirement system of  the  state,  which
  for  purposes of this section shall include any public retirement system
  other than the New York state teachers' retirement system, has been made
  optional by the head of the retirement  system  involved,  the  employer
  shall  inform  the  employee in writing of the right to join the system.
  Each such employee shall acknowledge  the  receipt  of  such  notice  by
  signing  a  copy  thereof  and  filing  it with such employer; provided,
  however, the failure to inform such employee shall not  in  any  way  be
  construed  to waive the requirement that membership for such an employee
  commences only when an application for  membership  is  filed  with  the
  system,  nor  shall  it  be  construed  to  waive any of the eligibility
  requirements for previous service credit.