You mean like stealing and hiding each other's cars, having a 3 month pie tour de force, filling up cars with crickets, erecting fake garages across the facility, all the practice helmet cams they have, and just general tomfoolery that happens every year anyway? That kind of distraction?
Why isn't anyone looking at the other side of this thing? What if the presence of HBO makes them all serious, and they take it as an opportunity to showcase how badass they are? Prove to the world that they're not a freaking door mat. The rest is just cameras off to the side and interviews. They have that stuff anyway without HBO. Billick (who did the first Hard Knocks) said that it actually energized his team when they were there. The distraction, if any, would come from players trying to mug for the camera and try to make the show about them. But I don't think Fisher would be the kind of guy to let a player screw off and become a ham when there was work to be done.