Problem needs fixing urgently: an instructor who adds spaces accidentally at the end of the unit field produces an error that is exceedingly hard to catch. This can negatively impact on the perception of Moodle since it makes it appear that Moodle is simply getting things wrong and does not work at simple tasks. This also affects 2.0 even with the separate unit entry field.
For example if metres is accidentally entered as "m " in the question editor then all students entering a response of "<correct value>m" will get it graded as wrong, even if they add the space since the space is stripped from the students response.
Strip trailing spaces from the instructor entered units in the form. Not sure about MOODLE 2.0 (where the problem still exists) but a call to 'trim()' in the form parsing code in question/type/<typename>/questiontype.php should be a quick fix for the very hard to catch trailing space issue.