A loop of rope is an invitation for a horse to get stuck. Margentino also recommends panic snaps for anything that hangs. All of the above applies to the washstall, with the addition of watching out for the water. Floors must be non-skid when wet. Standing water leads to mold in the summer and ice in winter time.
Panic snaps are more likely to rust with constant exposure to moisture.
Lights need to be covered so that stray water does not hit the bulb and cause it to explode. Electrical outlets for clippers or vacuums need waterproof covers. Equipment in a wash stall should be kept to the required minimum. Treat the space as a work area and not an extra closet. Keep shelves for brushes and shampoo high enough so that a shifting horse does not hit the shelf with his hip.