I would like to know if there are sites who actually use Tag 0020,000D Study Instance UID by the MWL Server.
If this tag has no value in it, the modality will create a value itself when a DICOM Object is made.
The PACS can index the objects according to the Study IDs, Study Instance UID etc.

So, what could be a reason why a site has the need to enter a value in Tag 0020,000D as part of the tagslist and offer it to the modality by the MWL Server ?