Joker's Wild actually had an 85% clearance rate in Feb. of 1975, so I don't think there would be much of an issue. In *most* cases, it was a medium size market that yanked a show (in Joker's Wild's case, that would include Dayton, Syracuse, Binghamton, Shreveport, Des Moines, Tulsa, Jackson [MS], Omaha, San Antonio, etc.). The huge ones didn't knock them out because they were O&Os, and the smaller ones didn't knock them out because it would often be too expensive. You were more likely to get a Central Time Zone pre-emption than any other, mostly because of the 9 AM thing.
In doing research of old TV stuff, I think we would all have drooled over Great Falls, MT. They had no NBC station, so the CBS station actually picked up 5 of the 6 NBC shows, missing only High Rollers, and was nice enough to try to have them away from the ABC station's shows. So instead of having to make choice after choice, only 3 slots had conflicts.
9:30-HS (CBS)
10:00-Jackpot (CBS)
10:30-Blank Check (CBS)
11:00-Celeb Sweep (CBS)
11:30-LMAD
12:00-Pyramid
1:00-TPIR
1:30-MG
2:00-Tattletales or Moneymaze
2:30-Wheel of Fortune (CBS)
3:00-Gambit
3:30-NYSI or Big Showdown
4:00-Joker or Split Second
5:00-Password All-Stars
Most surprisng in the usual two station markets, where it was CBS and NBC, the one show cleared most often from ABC other than sports would be Password. Even in 1975.
--Mike