Factual error: You can see the 3 point line painted out on the basketball court, they never had 3 point lines in the 50s. (00:21:55)
Factual error: The flag on the fire engine has 50 stars on it. In 1958, the US had 48 states. (Alaska and Hawaii joined in Jan and Aug of 1959 respectively). NB. the flag shown outside the school earlier in the film is correct. (00:48:45)
Factual error: When Reese Witherspoon's character is sitting at the desk reading, there is a cheerleading trophy and the cheerleader on it is wearing a mini skirt, - they didn't have mini skirts on the cheerleading outfits then. (01:08:20)
Factual error: When the townspeople try to undo the changes brought about by David and Jennifer's presence, they declare that only certain recordings will be permitted, including those of Jack Jones. The action takes place in 1958. Jack Jones did not sign his first record contract until 1959.
Answer: To me it never looked like a montage. It was just someone flipping through the channels (channel surfing) until they got to "TV Time" where they stayed to watch the commercial for the PleasanTVille marathon. People (especially before DVRs) sometimes just flip through the channels looking for something to watch, especially if you don't know what's playing on each channel.
Bishop73