Currently, if you go to the metadata schema for assets, you can leave the field blank when you use the tag field, as this is not required.
If you need that the user completes all the information in the metadata, including the tags, it wouldn't have the option to force the user to fill in the value
Use-case:
Current/Experienced Behavior:
Tag namespace required validation that does not exist today. So the user can leave this field blank.
Improved/Expected Behavior:
Environment Details (AEM version/service pack, any other specifics if applicable):
This has been reported to the engineering under the internal reference ASSETS-24232. The product team will triage this request to verify feasibility based on the prioritization model. This post will be updated according to the Jira request status.