I do not empty my tank, but merely pull the line off the muffler and connect the two lines from the tank together. This seals the fuel in the tank, as well as if it were in the fuel container.
Probably overly motherly, but it was always considered a bad practice to leave fuel in the tank. It attacks the klunk (especially if there is also moisture present - as in a partially full tank with air) and can soften the fuel lines. Maybe the newer plated klunks and silicone fuel lines prevent this, but if you find a junky klunk lying loose in the tank because the tubing lost it's elasticity and grip you know why. Alcohol attracts moisture.