Whole house DVRs. Do the slave TVs have cable running to them?

Generally you will have 1 central master DVR, and a bunch of receivers. The receivers cannot record. They simply access the master DVR for recorded programs, or they can watch Live TV. This may use up one tuner on the Master DVR, meaning the channel may change if the Master DVR needs it to record a show.

DirecTV's Genie DVR system can use a wireless connection for the receivers, however Dish Network's Hopper DVR system does require its receivers use wires (RF co-ax) to connect to the central DVR.

I don't know if the cable companies have a similar setup, or if they simply give you a stack of independent DVRs.

One TV in the house is connected to the DVR. For other TVs, each has its own receiver. The DVR and all receivers are connected (cable or wireless) to the system router. The DVR is controlled from a secondary TV through its receiver, to the router, to the DVR.