At first I misread the word “show” as “shut” …

Many if not most of the oldest broadcast stations used channel 2 or 3, since they were first (there was no channel 1, VHF 2-13 was all the FCC allowed (and available channels were limited to prevent interference with each other’s signals in a given area) & broadcast stations vied for the lowest numbers.

Channel 4 was an option for those with a local broadcast station on channel 3.