^ I am sure copies of ERs were given to the opposition candidates. They can tell it from the election returns whether or not somebody voted for them. They also have poll watchers, of course. I was watching ANC last night and even Adel Tamano could not argue with Tonypet Albano that the ERs in Maguindanao show that there were also votes cast in favor of the opposition candidates but it does not negate the fact that TU candidates made it on top 12.
If they really have evidence, they can go to court, not with the media. Media can accept almost everything even without basis, just for the sake of reporting it. The courts will have to dwell on pieces of evidence than hearsay though.