Nothing in this chapter shall be construed to mean that, on any special occasion where it appears to be satisfactory and beneficial to both employer and employee, they shall not have the right to agree, either verbally or in writing, as to where and at what time, other than every 15 days, wages shall be paid; but it shall be unlawful for any employer to require any employee to enter into any such agreement as a condition to entering into or remaining in his or her service.