MediaCom in Bainbridge, GA got busted for this. They were using Dish Network to pull in WSB-TV Atlanta and a few other stations. MediaCom was sued and they had to pay damages.
The now defunct city-owned cable system in Acworth, GA (a suburb of Atlanta) was using Dish Network to pull in the national feed of TBS. They did not carry the local channel 17 feed at all. They were sold to another company in 2006 that shut the system down months later and sold the base to Comcast (yes...there was competition in Acworth for a while).
The dish companies have no desire whatsoever to help cable companies. The Atlanta big-4 (WSB-TV, WAGA, WXIA, WGCL) are on AMC-10 satellite, so arrangements can be made there. But outside of Atlanta, Denver, and a few other markets...most stations do not link to a big-dish satellite. DirecTV and Dish get their signals either from a fiber link or OTA sent to a contracted data facililty that puts it on a long-distance fiber link to Colorado (Dish) or California (DirecTV).
IPTV solutions are coming out that can solve this problem by offering direct links via fiber over long distances...the issue is cost.
BTW...common carriers are OTA broadcast signal from the main station or a translater/repeater, microwave, or land lines (copper, coaxial, or fiber - leased from the phone company or otherwise).