So I parsed your comment wrong.  You meant a non-(ascii,  period or dash), rather than (non-ascii), period or dash?  Okay.  It might be good to restructure the comment a little.  And just because we don't allow users to use emails with non-ascii doesn't mean that non-ascii might not work.  But the course_num is not likely to contain non-ascii if it's going to be in a url.  So this is fine.  Just the comment.