TAP WD 1.0: question on query types

[Alberto Micol]

Quoting par 1.1:
 > TAP services distinguish three different kinds of query [...]: data  
queries, metadata queries, VOSI

Shall I read that in the sense that it is NOT possible to build a  
query that involves _at the same time_
both data and metadata tables?

Note: such distinction is already broken by the special MAXREC=0  
feature described in 2.3.7
whereby a data query results into a metadata votable...

I wonder
if it is useful to make such distinction at all,
or
if it is instead may own way of reading "TAP services distinguish..."
that is too strict... ? But if that confuses me, it might confuse  
others... maybe good to clarify
in the document?

Thanks,
Alberto