V FAQ : Baseline Feature : Can a non-version-controlled resource have a DAV:version-controlled-configuration property?
All members of a baseline-controlled collection (that are not members of another configuration) have a DAV:version-controlled-configuration property that identifies the version-controlled configuration whose root collection is that baseline-controlled collection. The state of a non-version-controlled member will not be captured by versions (baselines) of the VCCn identified by its DAV:version-controlled-configuration property, but this property is still useful because it indicates the VCCn that must be checked out in order to place that non-VCR under version control.