I'm actually surprised that all wiring went through that Mediacom box. Up this way, all company owned boxes are separate, and usually only for Phone and Internet purposes. However, the original owner (I'm only the third owner of the residence) finished the basement and ran his own wire for Cable. There is a sense of entitlement for Cable installers that isn't true for Satellite installers. Dish came out, ran their own lines (which is comon practice) and removed only one jack in the basement to set up TV 2 on my receiver, which he handed to me and gave a full explaination. A few years later, another installer who ran new wiring only cut Dish wires and left my owned wires in tact. When Comcast came a few days before Dish's original install for phone and internet, I had to demand that the installer leave the basement lines alone, where he was trying to justify that they weren't needed, and in his way.
My parents had FiOS installed. Becuase they are clueless in this area, they asked me to be there for the install. The Verizon installer, asked me about any wiring that was inside the house; however, he did cut Comcast's wiring outside the house. When I asked why, he said that it wasn't needed. I explained that it was up to us to determine what was needed on the house. He finished the install and didn't say much after the incident.
But to get to the OPs coment, All lines here, outside the house are ran on the side of the house and not boxed in. So I'm confused why DirecTV and Cox put wiring inside Mediacom's box. It's either DirecTV and Cox tried a quick easy install, or more likely, Mediacom is blowing smoke up your butt about it being their box. Knowning how much Dish and DirecTV have simular install practices, and dealing with Dish first hand, I would believe that DirecTV would have the same precision with installing service.