Passenger loading and unloading is supervised by lift operators. Their primary purpose is to ensure passenger safety by checking that passengers are suitably outfitted for the elements and not wearing or transporting items which could entangle chairs, towers, trees, etc. If a misload or missed unload occurs—or is imminent—they slow or stop the lift to prevent carriers from colliding with or dragging any person. Also, if the exit area becomes congested, they will slow or stop the chair until safe conditions are established.