i agree that this is possible...so, lets do a cost-benefit analysisn
so, if you waive the right to see...
cost: some programs may see it as a red flag
benefit: you are assured that some less than stellar letter is not being sent to all of your favorite programs
if you do not waive the right to see
benefit: programs will be happy, and not see it as a red flag
cost: potentially loosing ALL/MANY of your interviews due to a weak letter.
in short, you can be way to screwed by not seeing your letters to offset the little gain you may realize by waiving. another factor is for us internationals...the impracticality of getting letter writers to send everything direct to ECFMG and doing it correctly in a timely manner even gives us a valid reason to gather these letters ourselves...you can easily defend it with a PD if discussed. simply say "as a physician, i want to go to battle for my patient with the best possible tools, procedures, skills and drugs that are available. i apply that thinking to everything i do, therefore, i looked at all my options in recommendations, and found those most appropriate to the task at hand." or some other such nonsense...you get the point. it is way easier to defend looking at your letters than it would be to explain a bad letter.
just my take on the whole situation. i would love to waive, but i am just not willing to risk it for that little gain...
if nobody waives that right (it is a right, so why give it up so easy??) than program directors would not even consider it! so, lets start the new wave....look at your letters, everybody!!! see what those bastards are saying about us!