I assume that because you "would rather be absolutely sure so I just "pull da' plug"" that you use a wrist strap.
What are you using on the computer for ground if you pull the plug? By pulling the plug you may be grounded with the strap but now the computer is not. You put yourself in the exact same boat where you still need to keep in contact with the case to keep it grounded.

Ground is constant whether the switch on the strip is on or not.