Doubt anyone will hear much even with the open pads provided. With the default closed ones, no problem. :) Note that the closed pads will isolate quite well and the headset doesn't provide a way to hear what you yourself say into the mike.
I'm happy with this headset. It's closed, so I don't have to hear my PC while gaming, and the PC fan sound isn't picked up by the mike, and my friends say they hear me loud and clear. All I wanted. Except. Since it's closed, I don't hear my voice. I need that for recording, and also to make sure...