[spoiler]

You have 3 "holes" in your power strip outlets: Line, Neutral, and Ground. Now, a figure-8 can only have 2 wires inside it.

So, it's likely that you have Line and Neutral connected, while Ground is "floating" (not connected). Which means that, if something goes wrong inside the appliance, it can be dangerous for other appliances, and more importantly for you, too.

Especially if there are exterior metal parts inside the appliance that are grounded and a wire is touching the metal from the inside, too.