Any permittee shall have the right to keep the access area set forth in his permit free from parked cars, campers and other interference or disturbance, excepting as otherwise provided herein and excepting as provided in sections 606.36, 606.37 and 606.45 herein; provided, however, that any permittee exercising such right shall assume all risks and be liable for any and all damages or injuries to persons or property sustained thereby. Neither the State, the district nor the board shall be liable in any respect for any such damages or injuries.