It's not optional, exactly. In fact, it's part of the actual message that has to be delivered in the briefing right off the top by flight attendants to passengers. So they are informed that they must make an examination out the window to ensure there is nothing obstructing the way, and that there's no fire or smoke. They have to be able to operate the door. They are instructed how to do that.
Is that correct, Mr. Nourse?