8.3.1 - why uncapitalized "should" on tablenames with spaces?

["David A. Wheeler" <dwheeler@dwheeler.com>]

In "if the name of the table contains blanks, the name
should be quoted with apostrophes".... in general,
a specification should be as specific as possible.
Instead, say:

"if the name of the table contains blanks, writers
MUST quote the tablename with apostrophes;
readers SHOULD attempt to handle unquoted tablenames".

Also, what happens if there are quote marks in the
table name (e.g., "Joe's table")?  Are they
simply forbidden?  Are either (') and (") allowed?

--- David A. Wheeler