Sorry to post an old problem here. It is similar to this one, reported years ago:
http://moodle.org/mod/forum/discuss.php?d=53582
When a user doesn't respond to a required field in the questionnaire, the form gets reposted, causing a backslash il front of every apostrophe. This of course occurs in a text field.
I was able to fix the bug in the Journal module with "stripslashes".
Is there anyway I could do the same thing in the Questionnaire module?
François