FitNesse. UserGuide. FitLibraryUserGuide.
CommentFixture [add child]
The contents of a CommentFixture table are not considered:

any old stuff
is completely ignored
and not even coloured as ignored

This is also supported directly in flow.

If we want the table to be ignored and that to be reported, we can instead use:

any old stuff
is ignored
but it's coloured as ignored