Github user afs commented on the issue:
https://github.com/apache/jena/pull/341
To be clear: RIOT based parsing does not enforce IANA checking. It was just
that the RDF/XML parser didn't pick up the right IRIFactory via RIOT.
https://github.com/apache/jena/pull/342/commits/aecfaac0d631995120b77f22059291ffe6b9f06f---
