Since when has seeing, documenting, or filming an event made citizens subject to illegal detention, search, seizure or arrest? Police who detain individuals and confiscate materials which observe them acting badly and/or illegally need to be dealt with. They need to be identified, corrected and punished. The people they target need to be compensated at least with acknowledgement and apology. The only recourse for those individuals have should not be filing lawsuits.
Speaking out against authority and documenting abuses is not criminal … unless you are living in a country without civil liberties, i.e. a police state.