Must you Configure VSS Shadowstorage in a Guest OS to Use VMWare App-consistent Snapshots?

I am trying to track down what should be an obvious question, but one which seems to be ignored on the 'Net:

When you enable an application-consistent backup in VMware, it configures the VMware Tools component inside the guest operating system to take a VSS Snapshot, which then engages all of the active VSS Writers to ensure that all data write activity has been quiesced prior to the backup.  This is all the easy part.

Now for the hard part: What happens if the system administrator never sets up shadowcopy storage within the OS?  Or, more directly, do you need to configure the operating system's VSS storage (i.e. vssadmin list shadowstorage) in order for this to work?  I have seen references that VMware handles the snapshot duties, which would seem to imply that you do NOT need shadow storage configured.  However, I can also see where the VSS environment within the guest OS would depend on it, and it might refuse to allow a VSS snapshot to occur without storage being available.  Which is it???