WYSIWYG Source view often corrupts email templates and we avoid it where-ever possible within Campaign. Unfortunately it is the default option when creating new users and we have to always remember to switch Default from 'Design' to 'Source'. If this can be done at an org level for all new user creations, it would take away the risk of the Default 'Design' being left in place and existing templates becoming corrupted when they are opened in 'Design' view.