Common App and the FERPA waiver
Why should you consider waiving your right of access? Waiving your right lets colleges know that you will never try to read your recommendations. That in turn reassures colleges that your recommenders have provided support that is candid and truthful. While you are free to respond as you wish, if you choose not to waive your right, some recommenders may decline your request, and some colleges may disregard letters submitted on your behalf. Remember, even if you retain your right of access, you still won’t be able to view any recommendations until after you have been admitted to and enrolled in a college. In other words, FERPA does not give you the right to inspect recommendations before they are sent to your colleges.
For more information on FERPA follow this link: http://www.ed.gov/policy/gen/guid/fpco/ferpa/index.html