That's ridiculous. The previews are as much a part of the weekly episode as anything that came before. If the producers did not want you to see them, they would not show them.

If the writers want to throw us another twist, whereas conventional wisdom says it's Kirkman's wife being shot, they'll do a Reagan and have Kirkman be the one who is wounded. In which case, we won't find out whether he survived or not until the end of next season's first episode, giving us a dramatic scene of the…

The preview of the next episode clearly shows that neither Aaron nor Emily was shot.

Someone once asked John Ford why, during the chase scene at the end of "Stagecoach," the Indians did not simply shoot the horses pulling the stagecoach.