I am an electronics novice, so before I start cutting my cable, I want to ask people who know more than me.   

I have a project that has a USB 3.0 hub inside, and I want a single switch to handle the DC power and the USB connection to the computer. I saw a video of someone who put an inline switch on a USB 3.0 cable, and he switched power and ground. Is that necessary, or can I get away with switching only one?