This is a good step, but I am curious - how much are these laws enforceable? I was just reading that some Atlanta cops are not reporting to work - protest for the arrest of the cop who shot Rayshard Brooks. If that is the mentality, how much cooperation can we expect? Not talking about this particular NYC law, just in general.
However, the question is whether the reason you mention is a valid one. I believe a better one is that police officers stay home when they are supposed to work. In which kind of profession do you not get fired when you refuse to (show up on) work? Especially when there is unrest and violence on the streets, you are more in demand; your services are needed even more. In such times, staying home is akin to being a deserter in time of war.
I do not understand how one gets away with that. How do they? What is their leverage?