SAMPLE aggregate function

[Jeremy J Carroll]

I was thinking about SAMPLE and feel that there is a bug with the spec because 
it allows


A=1 B=2

as an answer from

SELECT (SAMPLE(?a) as ?A) (SAMPLE(?b) as ?B)
{
   { BIND(1 as ?a) BIND(1 as ?b)}
   UNION
  { BIND(2 as ?a) BIND(2 as ?b)}
}


I think the principal of least surprise would suggest that a single select 
should use the same solution to pick out the sample values, giving either 1,1 
or 2,2 as possible solutions here.

Jeremy