Basically the entire alliance is in the capital, except for Law. I feel like this makes him a potential target, it wouldn't make sense for Ryokugyu to go try and start shit with an alliance that took out 2 yonkos.
What if Ryokugyu captures Law to try to get at Luffy? The marines know Luffy would do anything for his friends, so they might be able to bait Luffy at pulling another marineford if they get Law.