Electric winches can also run away. A few years ago I hired a rigger to go aloft and he asked me to show him where the master off switch is, in case the control relay sticks. His partner manned the winch and he requested I stand by the master switch "just in case". He said they once had an incident where the winch wouldn't shut off when the momentary pushbutton was released. It gave me pause, and of course I was happy to stand there for his safety.

Years ago my boat dealer told me about a sister boat whose bow thruster wouldn't shut off due to a stuck relay. The boat had a near-miss with another boat and a dock, before he was able to get into the channel with enough forward speed to negate the side thrust. After hearing that I installed a remote cutoff switch for my bow battery called a "Battery Brain" and the remote is stuck on with Velcro just inside the companionway, easily reached from the cockpit. It kills power to the windlass also.