The definition of the element <q> contains the phrase "(separated from the surrounding text with quotation marks)". However, in section 3.3.3 (#COHQQ) it says, in reference to the various elements for quotation:
Quotation may be indicated in a printed source by changes in type face, by special punctuation marks (single or double or angled quotes, dashes, etc.) and by layout (indented paragraphs, etc.), or it may not be explicitly represented at all. If these characteristics are of interest, one or other of the global rend or rendition attributes discussed in section 18.104.22.168 Global Attributes may be used to record them.
So I think we should remove the above parenthetical phrase from the definition <q>.