No idle cutoff? +new owner question

The Stromberg carb has a completely different mixture setup from the Marvel. You CANNOT shut the engine down with the mixture. I just turn the mags to OFF. For a while I would close the valve to the carb and wait for it to run out of gas, but that takes a while and really doesn't accomplish anything. When you shut off the engine with the mag switch, you know the P leads are good! If for some reason a P lead breaks, You can close the fuel valve to stop the engine, it just takes a little time. After that, be aware that you have a mag that's hot all the time!
There was a guy at our airport that tried to shut sown his Ercoupe with the mag switch and it kept running. I'm assuming the fuel valve was stuck (many are) and he couldn't get it off. What to do? He got a buck of fuel and threw it into the intake so the it flooded the engine and it quit. Now THAT'S not dangerous at all! Ha! This is why it's IMPORTANT that the fuel valve be functional. I stop the engine with the mag switch but then I turn off the fuel. If for some reason the needle sticks in the carb you won't be dumping the header tank onto the hangar floor!