No police officer or fireman shall be required or requested for purposes of job assignment or other personnel action to disclose any item of his property, income, assets, source of income, debts or personal or domestic expenditures unless such information is obtained through proper legal procedures or is necessary for the employing agency to ascertain the desirability of assigning the police officer to a specialized unit in which there is a strong possibility that bribes or other improper inducements might be offered.