Arrested Palpatine
There's something I don't understand about Episode III. In the full trailer, there is a part where Mace Windu and a few other Jedi knights enter Palpatine's office and get their lightsabers out and arrest him.
But I don't understand that because what has he been arrested for and apparently, Palpatine tells them who he really is (Sidious), so if the Jedi didn't know that from before why did they bother use their lightsabers when they came in to arrest him.