I agree Mousavi is under tremendous pressure. He might be forced to pull it out or delay waiting for guardian council which would be the biggest mistake as others mentioned gives momentum to the regime.
People have to realize there is no going back. Either masses come out and force the regime to back out which ends up in those arrested free and stops the upcoming arrests and proscecutions, or stay home and watch many arrested, tortured, some prisoned, and others added to the watch list.
This is a window of opportunity that has opened. Dont allow GC to just say they will look into it and then give few more million to Mousavi and announce AN the winner.
You either go in as a team (that means masses pouring out), or you die and get prosecuted individually. People not pouring out and having so many prosectued will make it harder for people to risk their lives in the future demonstrations.