[mike31154]

I'm pretty sure there's no mocking intended here, he's just posting what happened to him with regard to a static charge. I see that the schematic at the bottom of the page (Neutral Transformer Approach) for the GFI device (from your link) contains a couple of coils which I assume sense the electromagnetic fields of the hot and neutral wires. This signal is fed to an IC which appears to have the function of controlling the relay which trips the device. The circuit is tuned to be quite sensitive so that it cuts the power with only a fraction of an amp imbalance. Any solid state device and inductance coil/transformer is susceptible to a static charge or EMI (electromagnetic interference). I'd say it's entirely possible that a static charge or EMI pulse could trip the device even if nothing is plugged into it. As long as line voltage is present at the input of the GFI device, it is sensing, whether it's actually powering something or not. If you read down farther on the page you linked to, there's a case of lightning tripping a GFI device. So IMO, there are more ways to trip these devices other than the 'designed' imbalance between line/neutral.