I've installed a number of these for my customers. They are tiny and the customer can request the IR eye for installation. It all works like it should. The nice feature is that all the channels are in HD where as before, with only the cable itself, the local channels were in HD and the rest in SD.

You might be able to install a splitter at the TV location and have one leg feed the CATV input on the TV and the other leg feed the cable box. The box connects to the TV via HDMI so the customer would have to change inputs to check the camera(s).