> The idea of remotely preheating my oven while I am not home still makes me shudder.
Electric ovens can be terrifying when they fail: https://www.youtube.com/watch?v=UrL_9K7rCz8
Mine was throwing a lot more sparks than in this video. It sounded like fireworks were going off in my kitchen.
What's the failure mode here? Heating coil making contact with the outer casing? Shouldn't that be caught by a residual-current circuit breaker?
In any case, generating lots of heat inside the oven is probably safer than doing it outside it.