It may be different now, but for a long time the networks only had East Coast and West Coast feeds. Stations in the Mountain Time Zone (two hours behind Eastern Time; one hour ahead of Pacific Time) usually took the East Coast feed and ran prime time network shows on delay (at one point the Denver stations handled the delayed feeds for the rest of the Mountain Time stations). In any case, stations in the Rockies would have the opportunity to censor network shows if they wished.It was also much more common at one time for local stations to pre-empt network programming, sometimes because local management had a problem with show's content. More often stations would dump weaker network programs because they could make more money with a local or syndicated show. Also in markets with less than three commercial VHF stations, the VHF stations would usually be primary CBS or NBC affiliates but dump weaker shows from their primary networks to clear more popular shows from ABC.