restrict column-level GRANTs to a single relation?

Fellow hackers,

I'm curious about the best way to handle something like this:
   GRANT SELECT (col1, col2, col3) ON table1, table2 TO grantee;

Is it reasonable to restrict this to a single relation, and throw an error
if multiple relations are specified?  That would require the preceding
grant to be specified as:
   GRANT SELECT (col1, col2, col3) ON table1 TO grantee;   GRANT SELECT (col1, col2, col3) ON table2 TO grantee;

The SQL standards don't seem to mandate the first form (unless I
misread?)..  Do y'all think this is a reasonable compromise?

-- kevin brintnall =~ <kbrint@rufus.net>