No entrance fee shall be charged to any person who is sixty-five (65) years of age or older and who is eligible to participate in the Rhode Island pharmaceutical assistance to the elderly program, and an entrance fee not exceeding one-half (½) of the established and posted rates shall be charged to any other person who is sixty-five (65) years of age or older at any recreational facility owned and operated exclusively by the state, excepting docking slips; provided, however, proper identification is presented as prescribed by the department of environmental management.