Robotics Systems Types

I need some way to identify classified objects in a 3D scene. For this I'd like to add an identifier to rst.classification.ClassifiedRegion3D. My preferred suggestion is to add a string field directly to the type. Another option would be to add it to the more general rst.classification.ClassificationResult type which is used by the previously mentioned one. But I think on a semantic level a classification result does not require a identifier field.
One could also think about using the rst.tracking.TrackingInfo type instead of a string, but semantically this is again not strictly for tracking purposes. Also it can be beneficial to use strings to describe objects in a 3d scene, because this enables the user to distinguish different types of objects.

Any thoughts on this?