[BirdOPrey5]

The wiki checkbox is coming from an add-on since that isn't part of vBulletin. My guess is that add-on requires the default text to be there so it can "add itself" to the template. When you edit the default text to remove what you want the auto-template edit fails so you don't see the wiki box either.

To do what you want will require editing one of the plugins from your wiki mod... Hard to know exactly what or which one- but one of them will be responsible for the template edit. You can change it to work with the default boxes removed and likely the same place you can edit the code to make the box already checked- but you're going to need some php experience to do this.