Trump doesn’t want them to watch for anything. He wants a bunch of skinheads with guns loitering around the polling places intimidating poll workers and people who want to vote. And when they break polling place security laws like getting too close and police come and arrest them (if they even do that and don’t just let them break the law) then they spread videos of, look we’re just monitoring but police are hauling us away, what are they hiding at this polling place? Or even better for Trump, violence and polling places getting shut down entirely. He just wants voter suppression and chaos.