help producing blank pages

[James Bailey]

I have some questions about generating "blank" pages.

Given an input file consisting of:
\paper { } \header {} \score { \markup \null }

The error log shows:
GNU LilyPond 2.13.23
Processing `test.ly'
Parsing...
test.ly:1:32: error: syntax error, unexpected \markup
\paper { } \header { } \score {
                                \markup \null }
test.ly:1:46: error: syntax error, unexpected '}'
\paper { } \header { } \score { \markup \null
                                              }
test.ly:0: warning: no \version statement found, please add

\version "2.13.23"

for future compatibility
Solving 1 page-breaking chunks...[1: 1 pages]
Drawing systems...
Layout output to `test.ps'...
Converting to `./test.pdf'...
error: failed files: "test.ly"

Except, the file doesn't fail, and generates expected output.

Whereas, given an input file consisting of:
\paper { } \header {} \score { }

The error log shows:
GNU LilyPond 2.13.23
Processing `test.ly'
Parsing...
test.ly:1:32: error: syntax error, unexpected '}'
\paper { } \header { } \score {
                                }
test.ly:0: warning: no \version statement found, please add

\version "2.13.23"

for future compatibility
error: failed files: "test.ly"

Two questions, why the "false" error with expected output, and why  
the actual error with no output?