Possible Errata on interpretation of BASE declaration

Hi All

Prompted by the discussion at
http://answers.semanticweb.com/questions/25510/sparql-base-keyword-multiple-
times-in-a-query I would like to raise a point for discussion which may need
to be added as an errata for SPARQL 1.1

SPARQL 1.1 introduced the ability for there to be multiple BASE declarations
in the prologue and for these to be freely mixed with PREFIX declarations in
any order which was a change from SPARQL 1.0 which only allowed a single
BASE declaration followed by zero or more PREFIX declarations.

What the discussion in the linked thread highlights is that the
specification does not explicitly state what the behaviour is when multiple
BASE declarations are present I.e. what Base URI should be used?

Personally I have always assumed (and implemented) the behaviour to align
with Turtle where the Base URI at any point is the one most recently seen
and seeing a new BASE declaration updates the Base URI resolving it against
the previous Base URI if necessary.  Jena ARQ which was of course written by
Andy Seaborne the editor of the 1.1 Query specification also agrees with
this interpretation.  However from the discussion it appears other tools
(OWLIM in the example given) don't and instead only honour the first BASE
declaration seen ignoring subsequent declarations.

I would appreciate clarification on the expected behaviour and if necessary
the addition of an appropriate errata.

Regards,

Rob Vesse