That's precisely how Stanford is proposing to structure their study. The patient won't know if the balloon was fully inflated or not. All patients post-study that were in the "non-inflated" category will then have the option of getting the real deal. Simple and eloquent.
That is not better than to use restenosis as controls. How would you know if somebody gets a restenosis one day after treatment? You will have to wait a pre-defined period or until he request a new test to find the restenosis, and then he should be removed from the "treatement arm".
Then, why not treat everybody and just compare the de-stenosed and the restenosis groups? We only need to prove that blood flow affects the health of MS patients.