They might be contractually obligated to pay. What argument do they have not to play/pay when they are going to go ahead and still play their conference games as of now? P5 is the one breaching the contracts. Even though they might have to pay, they are still likely coming out ahead financially by canceling the games. Don't have to deal with game day costs and they likely aren't missing out on ticket revenue.
The more I think about it, I'm pretty confident G5's will at least get a substantial fraction of their payout in whatever channel they have to go through. A P5 being proactive and paying may think they are doing it for good PR or whatever, but realistically they are just avoiding a bunch of legal fees + eventually paying out by doing so.