I know a guy who pulled the circuit breaker for the gear on a light twin. The circuit got disrupted, things got busy and a gear up landing ensued. The gear horn, the last line of defence was of course disabled when the circuit breaker was pulled.
My 02 cents
If it has a switch you can consider turning it off, but never pull a circuit breaker.
My pet peeve is that a lot of these emergencies are not handled realistically. That is the cb is pulled the stude rattles off the checklist and then the system is restored and on to the next emergency.
In the real world the initial emergency checklist items are often the easy part. Things get hard when you get to the "so what do I do now" pilot decision making.
I am a strong believer in having one simulated good emergency per flight but what's broke stays broke until you have landed, including having a discussion on how to write the snag.