As of the time of writing, this user has asked the same question 3 times and accepted answers for 2 of them only to open a new question with a slight modification to the requirements.
Does this appear to be deliberate abuse or misunderstanding of the way things work? What can/should be done (other than closing the old questions as no longer relevant)?
** Update **
I agree it appears to not be intelltionally abusive. The question then becomes how do we communicate to this and future users that such relatively minor changes (adding a constraint in each case here) should be edits to the original question. Or shouldn't they be?