Mandatory tableOwner property

In the R2RML spec the tableOwner property is required to qualify tableName
properties. I question this because it would seem to tie the R2RML mappings
to a specific database user. In my experience a given database schema can be
accessed via different users or installed on a separate database server
under a different user and it is desirable for a mapping to be usable
unchanged in multiple contexts. Maybe I am missing something?

For a tangible example of what I see as undesirable, notice that this test
case essentially hard-codes the user name "boricles":

http://www.w3.org/2001/sw/rdb2rdf/wiki/R2RML_Test_Cases_v1#R2RMLTC0000

-David