The plans are supposed to be legible. If they are not legible, you have the right to lodge a complaint. And if you do not pass the plan reading section because the plans were not legible, the ICC will not record the result as a failure. They will allow you to re-take the exam at no cost. The important thing though, is to make the challenge right after you take the exam (there are forms for this), and make a note of the set of plans you used for the exam.
In real life if the plans are very ineligble, then the risks for making construction errors increases due to guessing what's on the plans. msucog's suggestion that the plans be rejected is the right thing to do. But then, will the special inspector be backed up by his/her firm, RDP, and other major players...or be left to twist in the wind?