[DeleteSettings]
PreventDeleteCount=40
PreventDeleteSubtypes={0}
The Count variable (40) can be set to any number - if it is deleted, it is unlimited. The Subtypes variable is a list of subtypes that when present in a folder - you would want to prevent a deletion. Candidates for this would be discussions, projects, task lists etc. It is just a comma separated list. If it is removed, there are no restrictions.