Question: What if any are the requirements for "kill switch". I have a 21ft Bayliner with a cabin.
Answer: During a Vessel Safety Check the Kill Switch is one of the many items we check:
Safe Electrical and Fuel Systems:
The electrical system - Must be protected by fuses or manual reset circuit breakers. Switches and fuse panels must be protected from rain or water spray. Wiring must be in good condition, properly installed and with no exposed areas or deteriorated insulation. Batteries must be secured and terminals covered to prevent accidental arcing.. If installed, self-circling or kill switch mechanism must be in proper working order. All PWCs require an operating self-circling or kill switch mechanism.
As you can see the PWCs require a Kill Switch be used and in working condition. For your boat if one is installed and I've not seen a modern day boat without one, it must be in working condition. The test is to start the engine and pull the kill switch lanyard to kill the engine. It is generally mounted on the dash by the helm.