My document library supports several custom content types. When "Add new document" is clicked, the Browse dialog for uploading the file is followed by the Document Information Panel which is properly customized for whichever Content Type is chosen.
All is well except for the case of a user dismissing the DIP dialog by clicking Cancel.
The library has already stored the uploaded document but the metadata enforcement has been subverted by the user simply clicking Cancel. All content types have at least one required property which involves a choice from a Managed Metadata term store (there is no default term for this; would that tend to make this property "optional"??).
Is there a way to enforce the good intentions of the metadata designer somehow? Perhaps deleting the document if the metadata is not supplied?