The minimum cardinality property is a reference property which needs to be set on the component and therefore if this value is specified in code already it needs to be set via the property attribute of the component annotation.
While this works, we could make this closer to the reference and allow specifying it as part of the reference annotation by adding a new property.
Tooling (bnd) will process this annotation attribute (if set) and add it to the component properties - so no change in the DS spec itself, just support in tooling.
When there is a conflict during tool processing time, for example if the property attribute of the component annotation has also a value specified, this results in a build failure.