I looked at today's Pac 12 schedule. Let's start with yesterday, Washington played Stanford on FS1. Today, USC is at Colorado at 1PM (all times are PST) on Fox, WSU at Utah at 2:30 on Pac12, ASU at UCLA at 6:30 on Pac12, ORST at Arizona at 7:00 on ESPN2. Cal and Oregon have byes. So, there is no need for the alternate channels. Pac 12 teams are regularly televised on channels other than the Pac 12 Network and that network has the teams playing at different times so that there is little to no overlap.
Of course, that is for football, basketball is a whole nuther thing. Tomorrow there are 2 basketball games on at 1PM. There is nothing in the schedule, at the moment, to say how both games can be seen. Let's see what happens tomorrow...