the solenoid only stops fuel in the float bowl entering the main jet and going into the engine.
IT DOES NOT & NEVER WILL PREVENT AN OVERFLOWING FLOAT BOWL FLOODING INTO THE ENGINE WHILE THE ENGINE IS STOPPED.
Sorry to shout but it is important people understand which does what.
And yes it is prudent to put an inline fuel tap between the tank & the engine but that has nothing to do with the solenoid.