It's not the case. We had WISC-TV, the CBS affiliate, on channel 3 in our area. I seem to recall that one could switch between channel 2 and channel 3 on the Atari RF modulators, and later, VCRs could switch between channel 3 and channel 4. I think they used 2 and 3 because those were the first two channels, and the FCC wouldn't allow two adjacent channels in the same area, so one of the two would always be unused for everybody. (Oddly, there was no TV channel 1.)