I agree that such arrests are just a fear-inducing (i.e. "state terror") tactic. It sounds like the final decision to pursue/not-pursue charges was up to a judge, at least in this case. It would be interesting to know if the cops knew or cared about what (and what quality) evidence they had or didn't have.

Police arrested 57 people for criminal trespassing, a misdemeanor akin to loitering. Travis County Attorney Delia Garza's office said Friday all those charges have been dismissed after a county judge found insufficient evidence to proceed.