The chief appraiser, other members of the county property appraisal staff, and members of the county board of tax assessors may go upon property outside of buildings, posted or otherwise, in order to carry out the duty of making appraisals of the fair market value of taxable property in the county, other than property returned directly to the commissioner; provided, however, the person representing the board shall carry identification which is sufficiently prominent to permit the occupant to readily ascertain he is such representative and if practicable shall first advise the occupant of his purpose.