If the Big 10 and/or Pac 12 postpone the fall season, I expect that all of the P5 will follow. They will especially be leary of liability. If the SEC, Big 12, and ACC continue football while the rest of the NCAA does not and even one football athlete has severe problems from the virus, it would be trivial for a lawyer to argue that "everyone else involved in football knew the risks were too high and waited." Whether true and/or accurate or not, it will be a compelling argument that will end up costing those conferences money and potentially loss of control of their systems.