Metadata Portability for Digital Assets

I was checking out some DAM products recently at a show and came across a product feature that was highly touted by the company but ran counter to my own opinions. The feature is the ability to have metadata embedded within an asset

This feature is not new - MS-Office, PDF, TIFF, IPTC and other specs have metadata embedded within them. The XMP standard allows for embedding and is supported by many DAM systems. However, the metadata is usually either general like Dublin core or there for a specific use like
IPTC for newspaper photographers. The idea that this is a must-have for any DAM system and that the scope encompasses all asset types and all metadata, is an assertion that I never came across prior to this seminar.

While I like the open sharing aspect of this, I also have some serious concerns about whether this is required or even advisable in many cases. Some obvious areas of concern are:

• Security - metadata for medical imaging or legal documents can be very confidential to the point of being enforced by law. We all know that encryption is a temporary barrier for access to data i.e. time and processing power can always provide access. Furthermore, most asset repositories I have been involved with have a number of levels of access to information that can't effectively be managed when embedded within an asset, without compromising openness.
• Data integrity - what happens when an asset is created with incorrect or incomplete data, and proliferated by distribution. What then is the authoritative source of data? Is it not batter to manage this type of data centrally. While an asset may remain unchanged for a long time after it is complete, the data describing it will often be updated.
• Accessibility - a lot of metadata belongs in a database and is much more accessible in a database. It is easier to query, group and search on in a database than in files. This issue can be managed much more easily if you have a system that supports embedded metadata assets, so I consider it the lesser of the points, but it still makes more sense to me for the authoritative source for most metadata to be a database.

There many aspects of XMP that I find attractive, but I just thought I'd throw this one out for discussion as I would like to see what other think.