I think you spelled out the scenario very clearly for why and how the protests are astroturfed. It can work in both methods, natural protestors are arrested and the agitators are allowed to run free. Look at the different reactions on the different campuses. Columbia allowed to hold people hostage. Florida had riot police. In any case, I don't think the paid provocateurs or their handlers care if they get arrested. Meaning using arrests by itself as a litmus test doesn't help distinguish things. The outcome for both the scenarios you spelled out result in greater support for pro-israel and less support for anti-israel.